SELECT 
  product_id 
FROM 
  cscart_mb_ali_products 
WHERE 
  product_id IN (
    20589, 20590, 20591, 20592, 20593, 20594, 
    20595, 20596, 20597, 20598, 20599, 
    20600, 20601, 20602, 20603, 20604
  )

Query time 0.00021

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 (20589,20590,20591,20592,20593,20594,20595,20596,20597,20598,20599,20600,20601,20602,20603,20604)",
      "using_index": true
    }
  }
}