I know I must use the key on the correct crate.
I don't want to use the key, just open the chest please.

 

I mean, you can move the keys out of your inv slot, or press f to hold them in your offhand to open a chest. But yes I agree its annoying that whilst holding keys in your hand slot, that you can't open chests or containers. So ig support

 

I ran into this issue when moving DCs of keys. I had to drop a stack before I was able to open a chest to start depositing the rest because my inventory was filled with keys.