SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '647955ac6b8815790c26d6ea3b51b6c5d04746979f8a4a099b46021f4ba0affe' 
  AND token = 'rpywJbE6/WUvpaQLZDiXwRz1zNayVbCLQ5VonqNH+hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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