public static <K, V> KeyQuery<K, V> withKey(final K key) {
        Objects.requireNonNull(key, "the key should not be null");
        return new KeyQuery<>(key, false);
    }
Creates a query that will retrieve the record identified by {@code key} if it exists
(or {@code null} otherwise).
@param key The key to retrieve
@param <K> The type of the key
@param <V> The type of the value that will be retrieved
streams/src/main/java/org/apache/kafka/streams/query/KeyQuery.java