keyId 
  Returns only grants for the specified KMS key. This parameter is required.
Specify the key ID or key ARN of the KMS key. To specify a KMS key in a different Amazon Web Services account, you must use the key ARN.
For example:
- Key ID: - 1234abcd-12ab-34cd-56ef-1234567890ab
- Key ARN: - arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey.