I Sell Time at a Convenience Store

Chen Ye, a convenience store clerk who works the night shift. My daily job is to sell instant noodles and collect cash. A strange old customer came this day. "Hello, I want to buy a copy of time, ten minutes from three years ago." Because of this sentence, Chen Ye was left behind three years ago. But he gradually discovered that all strange things happened due to his own influence. Which came before the chicken, the egg, or the egg, the chicken?