How to say in Spanish "Would you keep these keys for me?"

How to say in Spanish "Would you keep these keys for me?"
 

The word "keep" is really tricky when translating from English to Spanish, I think because it means so many different things in English, whereas in Spanish there are different words to express it in different contexts.

In this situation, I was trying to ask my concierge on the first day I moved into my apartment if he could keep my keys for me while I went to get food. In this case, would you say "Podría usted quedarse con mis llaves" or would I use "guardar" or some other verb?

Guardarme o cuidarme mis llaves.

But, why would you do that?:thinking:

@Meaghang: If you say "quedarse con mis llaves", this would mean they would keep them for good. ;)

I agree with Alec's alternatives.

Or, "¿le puedo dejar mis llaves?" ("may I leave my keys with you?"), which is what an average Mexican would say. :D