In the side menu click Classes & Lessons > Lessons Admin.
Click the Students tab.
Set desired filters and click Search.
Click the + next to a student.
Hove the cursor over the number in the "Reg Slot" column.
You will see the day and time at the top of the pop up dialog, such as "-Tue at 5:30 pm".
If you do not see a day and time listed, it means someone eliminated that slot in the class after the student signed up for it. You will need to use the red [Move] link to move them to another slot or class.