Find a simple redis scheme related to voting

I haven"t used redis, before and ask everyone to give me a good plan

requirements are as follows:
redis maintains the serial number of the game vote. Before inserting the redis, you need to determine whether the serial number exists, and cannot insert duplicate ones.
requires a validity period of 8h
the collection sadd, used at the beginning, but the collection does not seem to support expire
now the key, key name is the voting sequence number, and the key value is 1.
although it can be satisfied, it feels that there are several bad places

.
  1. key value 1 is meaningless and a bit wasteful
  2. do I need a uniform prefix if I use key,? There may be other businesses that will also need to use redis,. All the key is in one place.

Thank you!

Mar.28,2021

key value 1 doesn't waste much.
usually key needs a prefix to distinguish
for example: product_, order_

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3c730-2c2f6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3c730-2c2f6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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