SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff46900fc1c6d4f88558546546c79e34d102fcb5c1f7d9f5435c9ff9113e610' 
  AND token = 'KGKrO/ZarijcR3Lckao0kcMN2MQmPyNG2Gmafkp3vp8=' 
  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