How can I mute the audio in my project temporarily

I am working on a video "slideshow" of photos with a music track underneath. I have already edited the audio to fade and transition at the proper places, so I don't want to delete & start over...but I am looking to just silence/mute my audio while I am editing so I don't have to listen to the song over & over.

I remember in older versions of FCP, there was options to hide/lock your various tracks at the far left of the timeline, but those aren't there anymore.

Thanks in advance!