This post contains some useful information about working with Redis.
There are multiple ways to query the TTL in Redis. The unit of time of the returned value can be confusing. Here’s each command and its returned value’s time format:
TTLcommand return value is in seconds
PTTLcommand return value is in milliseconds
INFOcommand is in milliseconds
Also, note that this average value avg_ttl is just an estimate based on random check of keys.