SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    9373, 9262, 9435, 9434, 9402, 5128, 5170, 
    4926, 4909, 4918, 4932, 5113, 5026, 
    5213, 4948, 4989, 4965, 4986, 5049, 
    5250, 4997, 4910, 5127, 4953, 5223, 
    5035, 4938, 4937, 4996, 5137, 5063, 
    5179, 5138, 5098, 4969, 5044, 4955, 
    5071, 5185, 5053, 4979, 5194, 4982, 
    5143, 5078, 5200, 5150, 5007, 5060, 
    5003, 5081, 5155, 5019, 5208, 5069, 
    5021, 5080, 5164, 5074, 5232, 5027, 
    5169, 5037, 5239, 5089, 5104, 5177, 
    5086, 5120, 5182, 5145
  )

Query time 0.00133

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "49.50"
    },
    "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": 121,
      "rows_produced_per_join": 121,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "25.30",
        "eval_cost": "24.20",
        "prefix_cost": "49.50",
        "data_read_per_join": "717K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (9373,9262,9435,9434,9402,5128,5170,4926,4909,4918,4932,5113,5026,5213,4948,4989,4965,4986,5049,5250,4997,4910,5127,4953,5223,5035,4938,4937,4996,5137,5063,5179,5138,5098,4969,5044,4955,5071,5185,5053,4979,5194,4982,5143,5078,5200,5150,5007,5060,5003,5081,5155,5019,5208,5069,5021,5080,5164,5074,5232,5027,5169,5037,5239,5089,5104,5177,5086,5120,5182,5145))"
    }
  }
}