SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1171, 1324, 1301, 1215, 1439, 1323, 717, 
    1217, 1343, 1338, 1337, 1174, 718, 1339, 
    1417, 341, 1275, 1216, 39, 1798, 1797
  )

Query time 0.00104

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": 21,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1171,1324,1301,1215,1439,1323,717,1217,1343,1338,1337,1174,718,1339,1417,341,1275,1216,39,1798,1797)"
    }
  }
}