SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8b0dbf246b6f71f25d8d2c2bdaab0cb9664fa17bf67bd62c52a5988994667b' 
  AND token = 't34+izr79jojhJTkv17tNcck2stRazcsxi1KbL6cHqE=' 
  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