User blog comment:Omega natsu2/Chapter 371: Tartarus Arc, Part 2: Song Of The Heavenly Dragon, Predictions./@comment-198.142.230.136-20140210052414/@comment-24066070-20140212024401

Just because there is a Draco constellation, doesn't mean there is a corresponding key.

There are loads of constellations, if there would be a key for all of them and Lucy would get them all, she'll be a bodybuilder before long thanks to carrying tons of keys around.