As of March 2021, Photoshop (version 22.3) now runs natively on Apple computers using the Apple Silicon M1 Chip.
You may see this error when trying to run the plugin:
Since KEY36 is an intel-based plugin, it does not work automatically on the M1 chip.
There is, however, a workaround suggested by Adobe to run intel-based plugins on Photoshop 22.3 and higher on an M1 device: Run Photoshop in Rosetta.
Follow these directions from Apple to open Photoshop in Rosetta:
https://support.apple.com/en-us/HT211861
After that, try running KEY36 and it should start working again.