Is it possible to get temporary access keys without using "static" access keys?

If you configured federation using external identity provider or configured AWS SSO, you can also get temp credential without long-term credential.

https://aws.amazon.com/blogs/security/how-to-implement-federated-api-and-cli-access-using-saml-2-0-and-ad-fs/ https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-sso.html

If you're on EC2 instance that has instance profile, you can get the temp credential using Instance Meta Data Service.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instancedata-data-retrieval.html