After reading separate video and audio tracks (in Shotcut), just export a portion of it as one video I am using Shotcut for my video editing (I am a beginner). I record one big video file, and one audio file separately, but when I load them into Shotcut actually I just need some portion of it. Is there a way then when I have read in the video and the audio into separate tracks to just export a portion of it (like from 1min - 2min or so)?

The way I do it now goes like this: I add them both to Shotcut, export everything, so that I end up with one big mp4 file. Then I reread this into Shotcut and just add the portion (with the blue/red-slider beneath the preview) I actually want (as a track), and then I export this again. But this additional step of exporting (and thereby rendering) everything I wish to skip, as it takes some time. So is there a way to do this?
I am using Shotcut in version 17.03.02. There are probably more ways how you can accomplish this.

The simplest is to mark in and out points in you video after adding it to the playlist. You can do this using keyboard (I - for in) and (O - for out) also while playing the clip. 

Then you can right click the file name in playlist and either Replace the clip with the new cut points or Insert cut, basically inserting a second clip with the cut points marked. Then you can append the file into the Video Track. Do the same with your audio file. Create cut points and append it to a new audio track. 

You can do some additional trimming in the track editor. For example using the Split At Playhead and delete the parts you don't want. That way you can trim both files to the same length. Now you have to export the project.