SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    243684, 51603, 119291, 275040, 277101, 
    277911, 275765, 276428
  )

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "8.67"
    },
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 8,
      "rows_produced_per_join": 8,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_products`.`product_id` in (243684,51603,119291,275040,277101,277911,275765,276428))",
      "cost_info": {
        "read_cost": "7.87",
        "eval_cost": "0.80",
        "prefix_cost": "8.67",
        "data_read_per_join": "61K"
      },
      "used_columns": [
        "product_id",
        "product_code",
        "product_type",
        "status",
        "company_id",
        "list_price",
        "amount",
        "weight",
        "length",
        "width",
        "height",
        "shipping_freight",
        "low_avail_limit",
        "timestamp",
        "updated_timestamp",
        "usergroup_ids",
        "is_edp",
        "edp_shipping",
        "unlimited_download",
        "tracking",
        "free_shipping",
        "zero_price_action",
        "is_pbp",
        "is_op",
        "is_oper",
        "is_returnable",
        "return_period",
        "avail_since",
        "out_of_stock_actions",
        "localization",
        "min_qty",
        "max_qty",
        "qty_step",
        "list_qty_count",
        "tax_ids",
        "age_verification",
        "age_limit",
        "options_type",
        "exceptions_type",
        "details_layout",
        "shipping_params",
        "facebook_obj_type",
        "parent_product_id",
        "__variation_code",
        "__variation_options",
        "__is_default_variation",
        "buy_now_url",
        "cod",
        "master_product_id",
        "master_product_status",
        "master_product_offers_count",
        "stock_id",
        "part_number",
        "s_part_number",
        "s_ordering_code",
        "ebay_template_id",
        "product_hash",
        "ebay_price",
        "package_type",
        "ebay_status",
        "ebay_override_price",
        "staff_notes",
        "is_stock_split_by_warehouses",
        "ab__stickers_manual_ids",
        "ab__stickers_generated_ids"
      ]
    }
  }
}

Result

product_id product_code product_type status company_id list_price amount weight length width height shipping_freight low_avail_limit timestamp updated_timestamp usergroup_ids is_edp edp_shipping unlimited_download tracking free_shipping zero_price_action is_pbp is_op is_oper is_returnable return_period avail_since out_of_stock_actions localization min_qty max_qty qty_step list_qty_count tax_ids age_verification age_limit options_type exceptions_type details_layout shipping_params facebook_obj_type parent_product_id __variation_code __variation_options __is_default_variation buy_now_url cod master_product_id master_product_status master_product_offers_count stock_id part_number s_part_number s_ordering_code ebay_template_id product_hash ebay_price package_type ebay_status ebay_override_price staff_notes is_stock_split_by_warehouses ab__stickers_manual_ids ab__stickers_generated_ids
51603 EL.UP.1572981 P A 137 1.00 294 5.000 0 0 0 0.00 0 1555175820 1599651602 0 N N N B N R N N N Y 10 0 N 1 0 0 0 7 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N Y 0 A 0 0 Letter N N
119291 ITE.HEA.72004478 P A 137 260.00 8 0.000 0 0 0 0.00 0 1555237800 1599651602 0 N N N B N R N N N Y 10 0 N 1 0 0 0 7 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N N 0 A 0 0 Letter N N
243684 TES.AMM.101620432 P A 137 1800.00 9 0.000 0 0 0 0.00 0 1555322760 1599651602 0 N N N B N R N N N Y 10 0 N 1 0 0 0 10 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N N 0 A 0 0 Letter N N
275040 VD520101 P A 137 3300.00 100 2.000 0 0 0 50.00 0 1569811740 1717388454 0 N N N B Y R N N N Y 10 0 N 10 100 10 30 10,12,13 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N N 0 A 0 GISJB506 GD520101 GD520101 GD520101 0 Letter N N
275765 1SFL707025R6911 P A 137 0.00 100 0.000 0 0 0 0.00 0 1599223800 1717261423 0 N N N B N R N N N Y 10 0 N 1 0 0 0 12,10,13 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N N 0 A 0 0 Letter N N
276428 2CDS271001R0021 P A 137 0.00 100 0.000 0 0 0 0.00 0 1599223800 1717261423 0 N N N B R Y 10 0 N 1 0 0 0 12,10,13 N 0 P F a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 N N 0 A 0 0 Letter N N
277101 1SDA068170R1 P A 137 78500.00 1 0.000 0 0 0 0.00 0 1599223800 1710059161 0 N N N B R Y 10 0 N 1 0 0 0 12,10,13 N 0 P F a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 N N 0 A 0 0 Letter N N
277911 1SCA121459R1001 P A 137 0.00 50 0.000 0 0 0 0.00 0 1599223800 1709742313 0 N N N B R Y 10 0 N 1 0 0 0 12,10,13 N 0 P F a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 N N 0 A 0 0 Letter N N