SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad54f3b8097e8ff38f51de6a90fc3601d55ee9452da4593498f46c3cece9661a' 
  AND token = 'jrbV6xn6I2HqNBGh1Xb1qzNwXkpv0bPr+tt82+L0VIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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