Simple Countdown Timer
Variable names
I find the get_ prefixes unnecessary on these:
get_year = check_time_now.year
get_month = check_time_now.month
get_day = check_time_now.day

That makes them look like functions.
Boundaries
This:
working_hours = datetime.time(7, 0, 0)
after_hours_am = datetime.time(6, 59, 59)

should probably just use 7:00 for after_hours_am. Otherwise, the time 6:59:59 given your current usage will still be considered working hours.
Likewise, this:
check_time_now.time() &gt; after_hours_pm

should use &gt;=.
An easy convention to follow that makes your boundary checking consistent is to always use intervals that are closed at the beginning and open at the end, i.e. 7:00 &lt;= time &lt; 8:00.
Redundant else
This:
    return datetime.datetime(get_year, get_month, get_day, 7, 0, 0)

elif ...

can use an if instead of an elif due to the previous return.
Don't repeat yourself
This return:
    return datetime.datetime(get_year, get_month, get_day, 7, 0, 0)

shares many commonalities with the other returns in its function. Factor out a new_day and new_hour variable assignment, then at the end of your function,
return datetime.datetime(get_year, get_month, new_day, new_hour)

Note that 0 is the default for the remaining parameters.
Timespan division
Trying not to do your own time math, this would be one option that doesn't require knowledge of time position multiples:
days = clock_tick.days
rem = clock_tick - timedelta(days=days)
hours = rem // timedelta(hours=1)
rem -= timedelta(hours=hours)
mins = rem // timedelta(minutes=1)
rem -= timedelta(minutes=mins)
secs = int(rem.total_seconds())

I don't like it, but built-in Python time libraries are kind of bad. Third-party libraries will reduce this to a one-liner format call. This is educational:
https://stackoverflow.com/questions/538666/format-timedelta-to-string