How to implement wait timers on the server for a mobile game?

Question

Java

Hello everyone, I ran into a problem with the implementation of wait timers (CD for items, used in clash of clans and other similar games). I think the point is clear.
What is the best and easiest way to implement this? I have 4 solutions in my head:
1) When the timer starts, a record is added to the PostgreSQL database, and then the server pulls these records. (PostgreSQL is used now, but I think that the implementation of such things for a relational database is too expensive ??)
2) We store everything in the server runtime (but the minus is immediately obvious - all timers flies if we restart the server)
3) Reddis (no work experience)
4) RabbitMQ (no work experience).
Java server.

Answer 1

www.quartz-scheduler.org