#!/bin/bash
for user in $(aws iam list-users --query 'Users[].UserName' --output text); do
  for key in $(aws iam list-access-keys --user-name $user --query 'AccessKeyMetadata[].AccessKeyId' --output text); do
    aws iam get-access-key-last-used --access-key-id $key --query '[UserName,AccessKeyLastUsed.LastUsedDate]' --output text
  done
done