SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    536, 454, 516, 670, 652, 698, 427, 648, 
    703, 687, 719, 425, 517, 428, 649, 683, 
    420, 1137
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "range",
          "possible_keys": ["parent"],
          "key": "parent",
          "key_length": "3",
          "used_key_parts": ["parent_id"],
          "rows": 23,
          "filtered": 100,
          "index_condition": "cscart_categories.parent_id in (536,454,516,670,652,698,427,648,703,687,719,425,517,428,649,683,420,1137)"
        }
      }
    ]
  }
}