SELECT 
  product_id 
FROM 
  cscart_mb_ali_products 
WHERE 
  product_id IN (
    21133, 21134, 21135, 21136, 21137, 21138, 
    21139, 21140, 21141, 21142, 21143, 
    21144, 21145, 21146, 21147, 21148
  )

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_mb_ali_products",
      "access_type": "range",
      "possible_keys": ["product_id"],
      "key": "product_id",
      "key_length": "4",
      "used_key_parts": ["product_id"],
      "rows": 16,
      "filtered": 100,
      "attached_condition": "cscart_mb_ali_products.product_id in (21133,21134,21135,21136,21137,21138,21139,21140,21141,21142,21143,21144,21145,21146,21147,21148)",
      "using_index": true
    }
  }
}