SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31a1474ac6a08253f1cb25f13be23d1ca090f1a4e00f775e788031b7fc12801f' 
  AND token = 'rRZ1uQh7BR0I+ydBrcUnlmvCgdBNKrP6503aO/BMnJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables