After testing several options to connect to a MSSQL database on a Raspberry PI through Python for a couple of jobs, the way it finally worked is using the FreeTDS driver through ODBC, using pyodbc.
Installation
sudo apt-get install freetds-dev python3 sudo pip3 install pyodbc
Code snippet
# Copyright Robert Eisele (https://raw.org)
import pyodbc
conn = pyodbc.connect("DRIVER=FreeTDS;SERVER=192.168.0.1;PORT=1433;DATABASE=db_name;UID=user;PWD=password;TDS_Version=8.0;")
cursor = conn.cursor()
for row in cursor.execute("SELECT * FROM t1"):
print(row)