Here are all the keyboard shortcuts you can use in the Timetracker app for Jira Cloud:
What it does and where
Open the Log Work dialog from anywhere in Timetracker or Jira.
g then t
Go to Timetracker from anywhere in Jira.
Move among fields in the Timetracker page or Log Work dialog form.
Ctrl + Enter
Save the defined work in the Timetracker page or Log Work dialog.
Ctrl + drag card
Copy a time record from one date to another on the Calendar page.
Double click on card
Open the Edit dialog on a worklog on the Calendar page.