The most common and most likely answer to this crossword clue is the 3 letter word UPS
I've seen this crossword clue in The Times
U
P
S
More clues leading to the result UPS
Buddy explains!

The straight part
We know that "Good times" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case good times = ups.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does UPS mean?
UPS noun- The direction opposed to the pull of gravity.
- A positive thing.
- An upstairs room of a two story house.
- To increase or raise.
- To promote.
- (usually in combination with another verb) To act suddenly.
- To ascend; to climb up.
- To upload.