Please check if the python version you are using is 64 bit. If not then that could be the issue. You would be using a 32 bit python version and would have installed a 64 bit binaries for the Python Extension packages.
[you can find any python libs from here][1]

[1]: https://www.lfd.uci.edu/~gohlke/pythonlibs/

Please check if the python version you are using is also 64 bit. If not then that could be the issue. You would be using a 32 bit python version and would have installed a 64 bit binaries for the OPENCV library.