Running jupyter notebook list will display all of the running servers on your machine. So doing this in the terminal after starting a cell in PyCharm will result in output similar to
Currently running servers:
http://127.0.0.1:8888/?token=f85145dda03dc598bbbfa6e53b93cbcb27629ea00cfd2105 :: /home/....
which contains the appropriate token for authenticating.