The time travel booster helps to save time and earn money right away. It shifts the time forward by the specified value (10, 30 minutes, or 1 hour), and you get the amount of money that you would earn by playing without a booster.
Time travel boosters also reduce the workshop build time and workshop order fulfillment.

   

If you have received time travel as a reward in the game, you can find it stored in the shop. In order to get stored time travel, open the shop and tap claim button under time travel that you need.