If you are inserting many undifferentiated (no attributes set) objects quickly (maybe you need their primary keys before you can get on with life) and applying_tokens to them on create, you'll end up spinning your wheels while running selects as fast as you can. This is because #inspect and Time.now won't change from one item to the next. Adding some randomness speeds things up dramatically.
The fix is a oneliner in plugins/token_generator/lib/token_generator.rb
token = Digest::MD5.hexdigest("#{inspect}#{Time.now}").first(size)
should be
token = Digest::MD5.hexdigest("#{inspect}#{Time.now}#{rand}").first(size)
I can supply a patch, but the fix is dead simple if anyone cares to apply it.