You could create a character style and give a shortcut to that.
Make sure the character style is set up to only change the kerning option.
Also beware of overriding existing character styles.
I can't create character style because my paragraphs have few different character styles inside, I look for a simple and fast way to locally change only kerning option for selected group of text (sometimes more then one paragraph at once). It's a pity that it is impossible to add shortcut to optical kerning option like for nobreak for example. I still think about simple script that can do it and that could be easily assign to any shortcut.
Try posting in the InDesign Scripting forum.