If the timestamp is detected, it will ignore them, simply because at index time the timestamp is internally converted to an epoch time (in seconds) and displayed in the timezone of your search-head / project.
If you want to manually extract the timestamp at search time, like with a field extraction, you can parse it as you want.
example
| rex field=mytimestamp mode=sed "/s/\[\]//g" | table mytimestamp
or
| rex field=_raw "\[(?< mytimestamp >.*)\]" | table mytimestamp
