SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1476, 1473, 1276, 1463, 1471, 1462, 1267, 
    1460, 820, 1472, 1464, 1470
  )

Query time 0.00105

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 (1476,1473,1276,1463,1471,1462,1267,1460,820,1472,1464,1470)"
    }
  }
}