SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2803, 2804, 2809, 2817, 2814, 2813, 2810, 
    2819, 2831, 2826, 2836, 2832, 2849, 
    2848
  ) 
  AND category_id != 414

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "22.41"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 42,
      "rows_produced_per_join": 42,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_categories`.`parent_id` in (2803,2804,2809,2817,2814,2813,2810,2819,2831,2826,2836,2832,2849,2848))",
      "cost_info": {
        "read_cost": "18.21",
        "eval_cost": "4.20",
        "prefix_cost": "22.41",
        "data_read_per_join": "148K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`s2cart`.`cscart_categories`.`category_id` <> 414)"
    }
  }
}