It seems the socket connection through paramiko (v1.10.0) is not stable. 
I have two computers. The python code is on the PC one. The connection sometime is successful and sometime is not (Same code). When the PC paramiko code fails (socket.error, 10060), I use my Mac via terminal ssh login the server and everything is fine.
I use set_missing_host_key_policy in the code. But the Mac has the key I guess. I typed yes when login at the first time.
If the unstable connection is caused by the hotkey, how do I get the host key? From the server or somewhere in my local folder (win7)?
Try switching off Windows firewall. It's a network error, it should not be because of SSH key problems.
Error Code 10060: Connection timeout
Background: The gateway could not receive a timely response from the website you are trying to access. This might indicate that the network is congested, or that the website is experiencing technical difficulties.
python paramiko module socket.error, errno 10060