Is it possible to assign custom (own) hotkey on any Google chrome extension? Looking for in-box or 3-rd party solution.
Look at the bottom of you extensions page, in newer versions (It's here in dev/canary for now, don't know about beta/release. Soon to be in release, I'm sure) there is a link 'Configure commands' to keyboard shortcuts options for main extension action (the one it performs when you click on extension button on Chrome toolbar)
Yes, you can. You need the following:
You'll find the ID of your desired chrome extension in the Webstore - e.g. https://chrome.google.com/webstore/detail/mgjjeipcdnnjhgodgjpfkffcejoljijf?hl=en
An AutoHotkey script for a hotkey like this would be: