With Clovis's journal fully decrypted, The Exo Stranger has tracked your final Stasis learnings to the Giant Exo Head within Creation inside Bray Exoscience.
It appears that to unlock it, you'll need to empower the Skeleton Key with Stasis one final time, before bringing it to the Giant Exo Head.
Follow the Exo Stranger's guidance to empower the Skeleton Key.