The quiz stays live for 24 hours. Once a quiz is open you have to attempt it within the next 24 hours, otherwise, it will expire and no marks will be awarded for the same. You can attempt the quiz anytime within the 24-hour timeframe.
As per Boardinfinity guidelines, it is mandatory to attend quizzes and exams in a particular time slot only. For instance, missing exams (all 3 attempts) or assignment submission deadlines will result in a minus 5% score.