SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1612, 1267, 1400, 1652, 1309, 1673, 1653, 
    1668, 1634, 1688, 1499, 1613
  )

Query time 0.00078

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 (1612,1267,1400,1652,1309,1673,1653,1668,1634,1688,1499,1613)"
    }
  }
}