门的钥匙用英语叫做 "key to the door"。来源方面，key是英语中常用的词，表示钥匙。而to the door这个短语是指钥匙的用途，也就是用来开门。例句：

I lost the key to the door. 我把门的钥匙丢了。

Can you please give me the key to the door? 能给我门的钥匙吗？

The key to the door was stuck in the lock. 门的钥匙卡在锁里了。