SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c00a8cbc063651ea589d6b5eba8bc93ce9b97d2add59e3f94b863438f17e6836' 
  AND token = 'IU/vEM5kCuNSjJNsXv2eeDcfPFUS7uD0Ep5Cd5dtq2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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