SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2718, 2722, 2713, 2850, 2852, 2719, 2997, 
    3018, 2732, 2733, 2859, 3007, 2734, 
    2714, 2715, 2725, 2736, 2737, 2716, 
    2720, 2726, 2730, 3116, 2900, 2924, 
    2728, 2721, 2927, 2727, 2731, 2851, 
    2717, 2729, 2849, 2735, 2848, 3089, 
    2712, 3005
  )

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "39.01"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 65,
      "rows_produced_per_join": 65,
      "filtered": "100.00",
      "index_condition": "(`cscart_db`.`cscart_categories`.`parent_id` in (2718,2722,2713,2850,2852,2719,2997,3018,2732,2733,2859,3007,2734,2714,2715,2725,2736,2737,2716,2720,2726,2730,3116,2900,2924,2728,2721,2927,2727,2731,2851,2717,2729,2849,2735,2848,3089,2712,3005))",
      "cost_info": {
        "read_cost": "32.51",
        "eval_cost": "6.50",
        "prefix_cost": "39.01",
        "data_read_per_join": "181K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ]
    }
  }
}