They are totally different words. "Par" is used in certain sports. It is a measure of how difficult a section is. For example, the first section of a golf course may be "par 3", meaning you would expect to get the ball in the hole in 3 swings. In other sports and games, the par may be a time. For example, there may be a par-time of 5 minutes to complete a stage in a videogame.

Par time is only something google associated with a video game I don't play. Perhaps a reference to golf and the number of swings that is ideal to finish the hole. Part-time is a job that only has limited hours worked.