Given that your key has expired.
$ gpg --list-keys
$ gpg --edit-key KEYID
Use the expire command to set a new expire date:
| # Making temporary redirect from http to https | |
| <VirtualHost *:80> | |
| ServerName example.com | |
| RewriteEngine On | |
| RewriteCond %{HTTPS} off | |
| RewriteRule (.*) https://%{SERVER_NAME}/ [R=307,L] | |
| </VirtualHost> |