Hi...
I checked it and found it that it is only for units and not for quizzes.
For achieving this, you can set a unit just before the quiz and set its start date and time according to the quiz.
Then in course settings enable the setting for previous unit/quiz completion, refer:
http://prntscr.com/feo1ht
Now the users will be able to continue the course only after completing the previous unit or quiz and since the unit start date time is set so the unit will be available only on that particular date and time after that the user can start the quiz.
This unit with start date can simply have an introduction page for quiz.