SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    4420, 4577, 4452, 4607, 8859, 4660, 4681, 
    4663, 4677, 4701, 4793, 5054, 5117, 
    8853, 5161, 8855, 8856, 4575, 4685, 
    4646, 4626, 8857, 8854, 4635, 4564, 
    4662, 4619, 4589, 4641, 4602, 4649, 
    4615, 9954
  )

Query time 0.00072

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "23.45"
    },
    "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": 56,
      "rows_produced_per_join": 56,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "12.25",
        "eval_cost": "11.20",
        "prefix_cost": "23.45",
        "data_read_per_join": "332K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (4420,4577,4452,4607,8859,4660,4681,4663,4677,4701,4793,5054,5117,8853,5161,8855,8856,4575,4685,4646,4626,8857,8854,4635,4564,4662,4619,4589,4641,4602,4649,4615,9954))"
    }
  }
}