A family of Microsoft word processing software products for creating web, email, and print documents.
You can assign a keyboard shortcut to a character style, as I'm sure you already know. Choose the "Styles" category at File > Options > Customize Ribbon > Customize, locate the style you want, and assign the shortcut.
During typing, to "turn off" the character style, you can press Ctrl+SpaceBar, which runs the ResetChar built-in command (as Hans has already suggested).