SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    789, 1375, 1230, 1227, 1770, 1769, 1420, 
    77, 1449, 1235, 1442, 1958
  )

Query time 0.00081

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (789,1375,1230,1227,1770,1769,1420,77,1449,1235,1442,1958)"
    }
  }
}