There is no shortcut assigned, but you can easily assign a new one:
Go to IDE settings | Keymap | Main menu | Window | Editor Tabs | Reopen Closed Tab (type reopen into the filter field to find it faster), right click on that item and select Add Keyboard Shortcut
Update: As stated in another answer, you can also use Ctrl + E to see a list of all recently viewed files. Additionally, you can use Ctrl + Shift + E to see a list of all recently edited files, which is handy when working on multiple files.