Assuming that you added code somewhere to enable the reCAPTCHA, then use your hosting File Manager (or a FTP CLient - I like WinSCP) and remove (or comment out) that code.
If you added the reCAPTCHA with a plugin, use File Manager/FTP to rename that plugin's folder, found in the wp_content/plugins folder of your site. That will temporarily disable the plugin from enabling the reCAPTCHA.
Once you have logged in, then find a better reCAPTCHA login plugin, perhaps. It looks as if that plugin you are using (assuming it's a plugin) doesn't recover gracefully from bad settings.