Yes, nowadays installaing pywifi via pip is problem. Upgrading pip is also not an option.
(se-toolkit) [ziya@ziya2018arch se-toolkit]$ pip --version
pip 10.0.1
(se-toolkit) [ziya@ziya2018arch se-toolkit]$ pip install pywifi
Collecting pywifi
Could not find a version that satisfies the requirement pywifi (from versions: 1.0.2.linux-x86_64)
No matching distribution found for pywifi
I would suggest to clone (or download the source) it into your python's site-packages directory, then install it.
(se-toolkit) [ziya@ziya2018arch se-toolkit]$ cd lib/python2.7/site-packages/
(se-toolkit) [ziya@ziya2018arch site-packages]$ git clone https://github.com/awkman/pywifi.git
(se-toolkit) [ziya@ziya2018arch site-packages]$ cd pywifi/
(se-toolkit) [ziya@ziya2018arch pywifi]$ pip install .
...
Installing collected packages: comtypes, pywifi
Successfully installed comtypes-1.1.4 pywifi-1.1.10
then use it.
(se-toolkit) [ziya@ziya2018arch pywifi]$ python
Python 2.7.14 (default, Apr 16 2018, 20:08:15)
[GCC 7.3.1 20180406] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pywifi
>>>