SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    9627, 9394, 4972, 4317, 4455, 5125, 5004, 
    4944, 5148, 4983, 4553, 5099, 5039, 
    4993, 5067, 5106, 5116, 4960, 5017, 
    5024, 4919, 5043, 5031, 5051, 4934, 
    5132, 5057, 5066, 5670, 4952, 5139, 
    5076, 4964, 5079, 5090, 4980, 4349, 
    5048, 5077, 4465, 5102, 5000, 4487, 
    5084, 5013, 4445, 4493, 4513, 5123, 
    5135, 5502, 5573, 8990, 4825, 8991, 
    4850, 5030
  )

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "30.66"
    },
    "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": 74,
      "rows_produced_per_join": 74,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "15.86",
        "eval_cost": "14.80",
        "prefix_cost": "30.66",
        "data_read_per_join": "438K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (9627,9394,4972,4317,4455,5125,5004,4944,5148,4983,4553,5099,5039,4993,5067,5106,5116,4960,5017,5024,4919,5043,5031,5051,4934,5132,5057,5066,5670,4952,5139,5076,4964,5079,5090,4980,4349,5048,5077,4465,5102,5000,4487,5084,5013,4445,4493,4513,5123,5135,5502,5573,8990,4825,8991,4850,5030))"
    }
  }
}