Boyd came off the bench late on to score in Sunday's 3-0 SPL victory over Aberdeen at Ibrox. It was his 49th goal for Rangers, and he is set to become the second fastest man in their history to hit the half century.
McCoist said: "Kris will be disappointed not to be playing. What pleased me about him coming on against Aberdeen, even more than his goal, was his attitude.
"I had the same problem here. And all you can do is come off the bench and score when you get the opportunity.
"Kris knows, as does Stevie Naismith, Lee McCulloch and DaMarcus Beasley, that they are part of a squad which, hopefully, can win things.
"Kris answered the men who pick the team in the right fashion by coming on and scoring."