Opencart Amazon S3 Regenerated Expired Link

I have integrated Opencart with Amazon S3 and was able to generate the download link successfully with an expiry time of 5 mins. How to regenerate download link for the same.

I just wanted to elaborate it in a better way. When the temporary link is generated for downloadable product in Opencart for Amazon S3, how to request for a new s3 temporary security credential before the old link expires.

Also how to request for a new s3 temporary security credential after the old link expires.

Thanks