Describe the bug

When the client pause write is set and all the keys in the server are expired keys, executing the randomkey command will lead to an infinite loop.

To reproduce

1. First, write a key with an expiration time. For example:

set key value ex 30

2. Second, execute the client pause command. For example:

client pause 60000 write

3. Third, wait for the key to expire, and then execute the randomkey command while the client pause is still in effect.

randomkey

Expected behavior

It is expected that the redis-server will return an expired key. However, in reality, there is no response at all, and the CPU utilization of the process reaches 100%.

Additional information

This bug will directly render redis-server unavailable.