How can I get alert, if my metrics(my_metrics) has consumed 0 messages from last 24 hours

My metrics are time series.

How can I get alert, if my metrics(my_metrics) has consumed 0 messages from last 24 hours.

I am trying to use below query but it seems not working
Queries I have tried:-
my_metrics[24h] == 0

increase(my_metrics[24h]) == 0