import threading
import time
def update_time(chat_id, message_id):
while True:
time.sleep(15)
bot.edit_message_text('новый текст', chat_id, message_id)
@bot.message_handler(commands=['start'])
def send_start(message):
sent = bot.send_message(message.chat.id, 'Сейчас 18:33:33')
threading.Thread(target=update_time, args=(message.chat.id, sent.id)).start()