The Dopesheet Filter
hotkey is what you want. Can you please show your hotkey entry? Did you check the spine.log for any hotkey errors? What OS are you using? Are you using a QWERTY keyboard?
We have found that the Dopesheet Filter
hotkey does not work in 3.8.99! It also does not work in v4 but we've fixed it in 4.0.39-beta. I'm afraid there is no way to make the hotkey work in 3.8, sorry!