ExpiredTokenException when it comes to mocking DynamoDB

[FaresKi]

Hi!
I'm starting to test my lambda using this package and am facing this ExpiredTokenException because I feel like I'm not correctly mocking my DynamoDB.
My lambda is pretty straightforward :

//lambda.ts
export const handler: APIGatewayProxyHandlerV2 = async (event: any) => {
  const body = JSON.parse(event.body)
  await doStuff(body);
}

//doStuff.ts
export const readItem = async function (
  id: body.id
  tableName: string,
  consistentRead: boolean = false
) {
  const response = await ddbDocumentClient.send(
    new GetCommand({
      TableName: tableName,
      Key: {
        id: id,
      },
      ConsistentRead: consistentRead,
    })
  )

  return response.Item as Item
}

My lambda test is similar to this :

...
AWSMock.mock("DynamoDB", "getItem", (params: PutItemInput, callback: Function) => {
      console.log("DynamoDB", "getItem", "mock called")
      callback(null, {})
    })
...

Am I doing this correctly?

Thanks in advance.