Before the Coffee Gets Cold by Toshikazu Kawaguchi. A small coffee shop has an unusual feature: if you sit in a certain chair, you can travel through time. But you can only stay in the coffee shop, anything you do in the past won't change anything in the future, and you had better finish your coffee before it gets cold or there will be dire consequences. Kawaguchi's novel is less about people using time travel to change fate and more about how people revisiting events can change their own emotional responses. If you have ever seen the Japanese series Midnight Diner, you will recognize the same understanding of human complexity and generosity toward human failings.
Special note: the first novel was originally a stage play - and the author has written three more books about the cafe.