SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f7c859776cf52b29828fd11d2507065f6b69812f5e86ad43838afcb122a8b1' 
  AND token = 'OC4UKVxLnOWCpeawB0rmY9wtgqczWnP2AgFbot+yj58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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