SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d406e3d7050ae818f2dfa4ca11766a73b95d7d93b8bba091877e007a431ac5' 
  AND token = 'FXUA891ief79rrEkihYJAa6tw1y+soZ703DuQU86bNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

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