A good start could be
time().
You also can access the Maxima function timedate(), use string command format, as this is the only way to convey an empty argument list.
Function: timedate ()
Function: timedate (T)
timedate() with no argument returns a string representing the current time and date. The string has the format YYYY-MM-DD HH:MM:SS[+|-]ZZ:ZZ, where the fields are year, month, day, hours, minutes, seconds, and time zone offset in hours and minutes.
timedate(T) returns the time T as a string with the format YYYY-MM-DD HH:MM:SS[+|-]ZZ:ZZ. T is interpreted as the number of seconds since midnight, January 1, 1900, as returned by absolute_real_time.
Example:
timedate with no argument returns a string representing the current time and date.
(%i1) d : timedate ();
(%o1) 2010-06-08 04:08:09+01:00
(%i2) print ("timedate reports current time", d) $
timedate reports current time 2010-06-08 04:08:09+01:00
timedate with an argument returns a string representing the argument.
(%i1) timedate (0);
(%o1) 1900-01-01 01:00:00+01:00
(%i2) timedate (absolute_real_time () - 7*24*3600);
(%o2) 2010-06-01 04:19:51+01:00

Martin Kraska
Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx