As a former basketball player who follows both the NBA and the English Premier League (EPL), I think it's difficult to come up with a phrase for "garbage time" in English football because of a couple significant differences between the two sports. In basketball, "garbage time" is used to describe a situation when one team is so far ahead of the other that there is virtually no chance for the other team to win so coaches can use this as an opportunity to "empty their benches" by substituting in many players who normally don't play very often. As a result of having so many inexperienced players on the court at the same time, lots of mistakes are often made and the play can get very sloppy and this is where the term "garbage time" originally came from.
In the NBA, an entire team of five players can be substituted in a game at the same time, but in the EPL it isn't possible to substitute in more than three players at once. Also in the NBA, the margin of victory doesn't matter whether it's one point or 51 points, but in the EPL, goal difference is an important tiebreaker. Two seasons ago Manchester City finished the season tied on points with Manchester United, but won the EPL championship because City had a better goal difference. I don't see how it would be possible to have a "garbage time" situation in the EPL since every goal that's scored matters and it also isn't possible to substitute in an entirely new team of players late in an English football match when one club has a large lead.