Reply to Mixing in key: basic questions

Returned to DJ'ing after a decade off, and now I see that mixing in key is really popular.

I've read up on the scales, but I have a question about the execution:

Doesn't pitch adjusting for beat matching throw everything off?

For example, I've brought all my music into Rekordbox, I know the keys, I'm good to go. But I still have to beat match, so everything will be thrown off if I plan a set based on key as the BMP's don't match.

Is key lock the only answer to this?