SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    12574, 12550, 12544, 12564, 12577, 12579, 
    12555, 12560, 12556, 12561, 12572, 
    12583, 12591, 12582, 12590, 12571, 
    12632, 12559, 12631, 15938
  )

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 20,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (12574,12550,12544,12564,12577,12579,12555,12560,12556,12561,12572,12583,12591,12582,12590,12571,12632,12559,12631,15938)"
    }
  }
}