SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75d338681e2199399539861f7127b00526f12bb83ab6a64576106cd0c37de56' 
  AND token = 'XxOvkOr8QSufqp+7vWcsXMTQryIfAwlzorbkF5wYz5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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