How to decrypt post data?

Question

Traffic analysis

Faced such that the post data from the service I need comes in encrypted form.
I would like to know if it is possible to decrypt them somehow, or to see them outside of the encrypted form?
I tried the selection method, but nothing happened .....
The sniff itself:

POST /api.php?mod=cart&act=cart_list&isenc=1 HTTP/1.1
Content-Type: application/json
Content-Length: 116
Host: app.**********
Connection: Keep-Alive
Cookie: MPHPSESSID=05c89dca0e7397392108add8b3bd2507; WEBF-dan_num=0; WEBF-email=igg72307%40euaqa.com; WEBF-user_id=4005020; avatar=%2Ftemp%2Fskin2%2Fimages%2Fdomeimg%2Fscrollimg.gif; c97018773-168513ic=c211140-92865-297905; usertype=0
Cookie2: $Version=1
Accept-Encoding: gzip

r6a0zoolCMgvRWLiopz4jPdX3VQie/ORausoOo7i6mARD1g/zTTeXUbHVP1ZoyVCL+yoNSfduk2fVm6q9z+OgOkH6NekN5ptXtPszGxK/U1p6jz7Mg==

Answer 1

You can't see all the text. And it's sad. And so it looks like base64 -at the end ==. True, as a result of decoding, some kind of nonsense with hieroglyphs.