Missing Key?

[FishEggsBang]

I recently got the hookshot, and now I'm backtracking throughout the other locations to find any collectables I may have missed, but I recently ran into a problem with the room that holds the corrupted antler, there's a gate in the way that's locked, and it claims I need a key to unlock it. I went back through the dungeon, found two empty key pedestals I must have gotten earlier, but no third key. I even went looking through walkthroughs on various websites but only a few have even mentioned the gate being there. Is there something I'm missing, or is this possibly a bug I just can't fix?

Any help would be greatly appreciated.

[Perseus]

This guide's video shows all three key before obtaining the bomb spell.
https://steamcommunity.com/sharedfiles/filedetails/?id=2566808531