SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2508, 2509, 2516, 2515, 2513, 2518, 2533, 
    2528, 2530, 2534, 2532, 2529
  ) 
  AND category_id != 414

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.81"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_categories`.`parent_id` in (2508,2509,2516,2515,2513,2518,2533,2528,2530,2534,2532,2529))",
      "cost_info": {
        "read_cost": "11.41",
        "eval_cost": "2.40",
        "prefix_cost": "13.81",
        "data_read_per_join": "84K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`s2cart`.`cscart_categories`.`category_id` <> 414)"
    }
  }
}

Result

category_id parent_id
2510 2509
2511 2509
2512 2509
2514 2513
2517 2513
2519 2518
2520 2518
2521 2518
2522 2518
2523 2518
2524 2518
2525 2518
2526 2518
2527 2518
2531 2518