I got it solved by installing OpenSSL according to the following recommendation: https://github.com/conda/conda/issues/8046#issuecomment-450515815
Corresponding ticket in the conda repository: https://github.com/conda/conda/issues/8046
Update: the problem (in PyCharm) should be solved in 2019.1 version (Early Access Preview build is already available https://www.jetbrains.com/pycharm/nextversion/).