What type of keys, and on what server? If you are talking about keys such as legendary and ancient, then I don't think so. These are meant to be keys/items that can be bought in order to boost a players riches/item value/ overall position in a season of whatever gamemode you are playing. You can always buy them from other players. If you are talking about vote party/vote crates then I don't think so either. These each are given to players for a certain reason, or a certain event. Both of these are from voting. There are a few examples that I can think of that don't follow this rule, such as /rankup (ancient/legendary keys) etc.
I say No
Keys in /shop would change the Manacube economy dramatically, I believe that adding keys to the shop {/shop} would decrease the Manacube economy which in this case they would lose tons of real-life money.