Yes .. but the "S" at the end of those are crucially important. People naturally search for the show timeS of a movie .. they do not search for the show time (without S), even if their intention is to only go to one specific show.
Also .. a separate point I just thought of .. I also think "Showtime" is the name of a movie magazine .. so might be a trademark issue as well since it could be argued people who search for "Movie" + "Showtime" are only really looking for Showtime Magazine .. whereas the same definitely could not be said about Showtimes (with the "S"), which would be fine.