Function checkAlreadyExpired

app/redis-6.2.6/src/expire.c:469–477

}

int checkAlreadyExpired(long long when) {
    /* EXPIRE with negative TTL, or EXPIREAT with a timestamp into the past
     * should never be executed as a DEL when load the AOF or in the context
     * of a slave instance.
     *
     * Instead we add the already expired key to the database with expire time
     * (possibly in the past) and wait for an explicit DEL from the master. */
    return (when <= mstime() && !server.loading && !server.masterhost);
}

/*-----------------------------------------------------------------------------
 * Expires Commands