Is there a way to mute/unmute a call using the side buttons?

Everyday on conference calls, someone will ask someone a question, followed by a 5-10 second delay as that person fumbles with their iPhone to Unlock it, close the current app, click the green bar across the top, then finally unmute the phone. It is so frustrating and takes too many steps.

My old BlackBerry allowed me to mute/unmute a call by hitting the side button. This would work during a call regardless if the phone was locked or not on the phone screen.

Has Apple thought about this?

Maybe someone has created an app for this? It would literally help out millions of users like me who are on conference calls all day!