A professional locksmith may have specialized tools which can hook and pull in the key. Depending on where the break occurred it may be necessary to lift pins out of the way at the same time.
Alternatively, if you can get into the house another way, it may be faster)/easier to disassemble the lock and push the key out from the back. Again this may require lifting pins out of the way unless the break is right at the face of the lock.
Note that if you can dismount the lock and take it to a locksmith, this may be considerably cheaper than having the locksmith come to you. (Or may not; in my area many other visits are now working almost entirely from a van or truck rather than having storefronts.)