SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1675, 1931, 1544, 1845, 1540, 1512, 1525, 
    1536, 1538, 1937, 1581, 1582
  )

Query time 0.00097

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 (1675,1931,1544,1845,1540,1512,1525,1536,1538,1937,1581,1582)"
    }
  }
}