SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5adc479104af0d2262faf35c1d260aadc983e5a9b28962539bf95bfddb2a7444' 
  AND token = 'YFnQIWLxHkaBrCafq8aOaNb6BNPl5ZDwpAEjnX1J2K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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