They sell clear keyboard covers although that is mostly for keeping them clean and being able to disinfect the cover than to protect the keys. That does change the feel of the keyboard a lot though.
I would not worry about it through, just use the thing. Don't use it with dirty hands or with any chemicals on it. Most of the time I see super worn out keys is from women who use perfume, makeup remover, makeup and the chemicals actually melt the keys.