Every 60 seconds, a minute passes in Africa.

That was my first thought as well, but I think he means things, not time. You miss this thing and that as you stare at your phone. So in that second of mindless scrolling, you missed things around you that might have added something to your day, to your life. So 'how much of your life do you let pass by' is not asking how many seconds of life did you let pass by (though that is the first thought upon reading), but 'how many things that could have affected your life- for the better or worse- do you let pass you by?'