I know that the big Mercadona (supermarket) behind The Era Park (sorry but I don't know the name of the street) definately
cuts keys. I also think that there is at least one place in the indoor market that do too. Good luck.
A guy on the`indoor market cuts keys and very cheaply. I've used his service and all the keys worked okay when I got them home. I think I only paid about 1 euro each