SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5e44888f5a05b9353364979839559e01ec0446eadbc39b6948217b9cde4b502' 
  AND token = 'FiEU3QBry6PBAUxpfL82qTvigd/PDR1ypArbuzA9FDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

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