The hourglass not done emoji symbolizes time running out.
Unicode: U+23F3
The hourglass not done emoji (⏳) depicts an hourglass with sand still falling, indicating that time is running out or something is still in progress. It's often used to convey a sense of urgency, impatience, or a countdown.
"I'm still working on the report ⏳"
"The concert starts in an hour ⏳"
"Can you hurry up? The movie starts in 20 minutes ⏳"