Basic Mixing : Sends : Muting Sends : Key Commands for Muting Sends
 
Key Commands for Muting Sends
Pro Tools | First provides key commands for muting sends:
Control-click (Mac) or Start-click (Windows) a Send Assignment button in the Mix or Edit window to Mute it and all sends below it on a track.
Control-Option-click (Mac) or Start+Alt-click (Windows) a Send Assignment button in the Mix or Edit window to Mute it and all sends below it on all tracks. This lets you mute all sends in your project with a single click.
Press Shift+Q to mute (or unmute) all sends on selected tracks.