Add connection.timeout variable assignment to your code. Defaults to 0 (timeout disabled), expected in seconds.

import pyodbc
import time

connString = 'SERVER=dbserver;PORT=1433;DATABASE=db;UID=dbuser;PWD=dbpwd;' + \
             'DRIVER=FreeTDS'
cnxn = pyodbc.connect(connString)
cnxn.timeout = 3
cursor = cnxn.cursor()

t1  = time.time()
cursor.execute("SELECT MAX(Qty) FROM big_table WHERE ID<10000005")
print cursor.fetchone()
t2 = time.time()
print t2-t1

cursor.execute("WAITFOR DELAY '00:00:30'")
print 'OK'

Add Connection.timeout variable assignment to your code. Defaults to 0 (timeout disabled), expected in seconds.

import pyodbc
import time

connString = 'SERVER=dbserver;PORT=1433;DATABASE=db;UID=dbuser;PWD=dbpwd;' + \
             'DRIVER=FreeTDS'
cnxn = pyodbc.connect(connString)
cnxn.timeout = 3
cursor = cnxn.cursor()

t1  = time.time()
cursor.execute("SELECT MAX(Qty) FROM big_table WHERE ID<10000005")
print cursor.fetchone()
t2 = time.time()
print t2-t1

cursor.execute("WAITFOR DELAY '00:00:30'")
print 'OK'