pytz_things.py

from datetime import datetime

import pytz

data = {
    "sub": [
        ["a1", "2024-07-01 07:39:41 UTC+0000"],
        ["a3", "2024-07-01 07:39:41 UTC+0000"],
        ["j5", "2024-07-01 07:39:41 UTC+0000"],
    ]
}

valid = []

current_time = datetime.now(pytz.UTC)
for username, date in data["sub"]:
    representation = datetime.strptime(date, "%Y-%m-%d %H:%M:%S %Z%z")
    if current_time <= representation.astimezone(pytz.UTC):
        valid.append(username)

print(valid)