The term to use should be "Expiry date".
Although the terms expiry and expiration are mostly interchangeable, the term 'expiration' has a primary meaning of breathing out or death.
The term 'expiry' however has a primary meaning of 'termination', especially the termination of a time or period fixed by law, contract, or agreement.
Some sources claim that 'expiry' is UK English, while 'expiration' is US English, but I have found little evidence of that, as the definitions that I have given hold in both the American and British dictionaries that I have checked.
'Expiration' = death
'Expiry' = end of validity