SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db80cd0851e650f3ccb53d593fb6927348311906b2ea5e1550fd586e1029151a' 
  AND token = 'N/ZdbGu9Agtusj3IklM+dnwPHgxSqJW20UqbP4OexSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

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