import openpyxl
import io
import boto3

s3_file = s3.get_object(Bucket=bucket, Key=key)
xlsx_file = openpyxl.load_workbook(io.BytesIO(s3_file['Body'].read()))

#for more on how to use openpyxl follow this link https://www.pythonexcel.com/openpyxl.php