SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2373, 2376, 2381, 2385, 2415, 2419, 2420, 
    2421, 2422, 2443, 2448, 2449, 2450, 
    2460, 2464, 2466, 2483, 2496, 2498, 
    2588, 2627, 2628, 2629, 2630, 2634, 
    2638, 2643, 2675, 2679, 2687
  ) 
  AND category_id != 414

Query time 0.00065

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "26.86"
    },
    "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": 43,
      "rows_produced_per_join": 43,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_categories`.`parent_id` in (2373,2376,2381,2385,2415,2419,2420,2421,2422,2443,2448,2449,2450,2460,2464,2466,2483,2496,2498,2588,2627,2628,2629,2630,2634,2638,2643,2675,2679,2687))",
      "cost_info": {
        "read_cost": "22.56",
        "eval_cost": "4.30",
        "prefix_cost": "26.86",
        "data_read_per_join": "152K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`s2cart`.`cscart_categories`.`category_id` <> 414)"
    }
  }
}

Result

category_id parent_id
2497 2496
2589 2588
2590 2588
2591 2588
2592 2588
2593 2588
2594 2588
2595 2588
2596 2588
2597 2588
2598 2588
2635 2634
2636 2634
2639 2638
2640 2638
2641 2638
2642 2638
2644 2643
2680 2679
2681 2679