Can I validate session tokens in AWS Lambda Function?

I am new to Shopify and I want to validate the session token in AWS Lambda Function that is generated in the Shopify Checkout UI Extension.

Currently, I am trying to send an API request to AWS and was able to run it, but the next step is to validate the tokens from Shopify.

Please see my current code:

Checkout.jsx (Shopify Checkout UI Extension):

AWS Lambda Function:

Testing the AWS API via POSTMAN

Console Logs When I Call the AWS API that is integrated with the Lambda Function:

My question is, can my AWS Lambda Function handle the shopify token validation? I was also told if I can dowload a .pub file? I’m not sure about this though. Or do I need another backend server like AWS EC2 that is the middleware between my Shopify UI Extension and AWS API/lambda ?

If either the two of the works, please help me how to achieve the validation of tokens. Thank you.