Reach 10000 points within 90 seconds in order to pass level 64.

1 star: 10000 points
2 stars: 20000 points
3 stars: 30000 points

Be sure to wait until the level is over, you may beat it with the remaining special candies. For those of you that have issues with Candy Crush Level 64:

Patricia Frederick’s Tips for Candy Crush Level 64

You’ve got to unlock the candies (and release the chocolate) so you have more room to create special candies.