How can I view submissions of form I do not have a key to?

Also I had encryption enabled by mistake on one of my forms (80163320967961). As far as I know I never downloaded or uploaded any key, so how can I decrypt these form submissions?

Unfortunately you need to have the key to decrypt any form that has been encrypted. If you lost the key you can not view encrypted data however you can disable the encryption to avoid new submissions being encrypted but you will not have access to the old encrypted data.

To disable encryption see illustration below.

Below is a related thread that will shed more light on form encryption:

https://www.jotform.com/help/344-What-Are-Encrypted-Forms-and-How-to-Use-Them-as-Expert