SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    64353, 64273, 64355, 64274, 64276, 64275, 
    64277, 64946
  )

Query time 0.00055

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": 8,
      "filtered": 100,
      "attached_condition": "cscart_products.product_id in (64353,64273,64355,64274,64276,64275,64277,64946)"
    }
  }
}

Result