Changing the keyboard shortcut

⌥⇧J doesn't work. How do I change it?

Another extension may already be using that combination. Chrome gives it to whoever asked first, and tells nobody.

Open Clearing's settings — the toolbox icon at the top right of the grid — and choose Keyboard shortcuts. It shows the combination currently assigned, or "Not set" if there isn't one. Click Chrome settings and Chrome's own shortcuts page opens, where you can set whatever you like.

Chrome keeps some combinations for itself and will simply refuse those. If another extension holds the one you want, Chrome tells you which, and you can clear it there.