diff --git a/doc/user/errcode.xml b/doc/user/errcode.xml
index c882838da5a0fb44a31f3ead9b6451ebf9bcfc42..affe269ee40413b5213e88a0ecdf4741068b3986 100644
--- a/doc/user/errcode.xml
+++ b/doc/user/errcode.xml
@@ -55,6 +55,12 @@ of existing codes.</para>
     </para></listitem>
   </varlistentry>
 
+  <varlistentry>
+    <term xml:id="ER_KEY_CARDINALITY" xreflabel="ER_KEY_CARDINALITY">ER_KEY_CARDINALITY</term>
+    <listitem><para>Key cardinality is greater than index cardinality
+    </para></listitem>
+  </varlistentry>
+
   <varlistentry>
     <term xml:id="ER_NO_SUCH_SPACE" xreflabel="ER_NO_SUCH_SPACE">ER_NO_SUCH_SPACE</term>
     <listitem><para>Attempt to access a space that is not
diff --git a/include/errcode.h b/include/errcode.h
index 8c7a22bf221196b9019a5eea4b0847d1230f28d3..19edbd1e34522cbefb6f94dc8e7e1abb3c38856c 100644
--- a/include/errcode.h
+++ b/include/errcode.h
@@ -101,7 +101,7 @@ enum { TNT_ERRMSG_MAX = 512 };
 	/* 44 */_(ER_UNKNOWN_UPDATE_OP,		2, "Unknown UPDATE operation") \
 	/* 45 */_(ER_UNUSED45,			0, "Unused45") \
 	/* 46 */_(ER_UNUSED46,			0, "Unused46") \
-	/* 47 */_(ER_UNUSED47,			0, "Unused47") \
+	/* 47 */_(ER_KEY_CARDINALITY,		2, "Key cardinality %d is greater than index cardinality %d") \
 	/* 48 */_(ER_PROC_RET,			2, "Return type '%s' is not supported in the binary protocol") \
 	/* 49 */_(ER_TUPLE_NOT_FOUND,		2, "Tuple doesn't exist") \
 	/* 50 */_(ER_NO_SUCH_PROC,		2, "Procedure '%.*s' is not defined") \
diff --git a/mod/box/box.m b/mod/box/box.m
index 3673757696828525e08a594b8fba1f6c8a50b42e..75673f25b8ecaeb97fa8045023e524d9dd98cce9 100644
--- a/mod/box/box.m
+++ b/mod/box/box.m
@@ -897,6 +897,12 @@ process_select(struct box_txn *txn, u32 limit, u32 offset, struct tbuf *data)
 
 		void *key = NULL;
 		if (key_cardinality) {
+			if (key_cardinality > index->key_def->part_count) {
+				tnt_raise(ClientError, :ER_KEY_CARDINALITY,
+					  key_cardinality,
+					  index->key_def->part_count);
+			}
+
 			key = read_field(data);
 
 			/* advance remaining fields of a key */
diff --git a/mod/box/tree.m b/mod/box/tree.m
index 17b191c0858b9864a1fa909c4cab59ed5495ea1f..c1b75a31d49bd2ee8b9961798995fc8e218396c1 100644
--- a/mod/box/tree.m
+++ b/mod/box/tree.m
@@ -323,7 +323,8 @@ fold_with_key_parts(struct key_def *key_def, struct key_data *key_data)
 
 	memset(parts, 0, sizeof(parts[0]) * key_data->part_count);
 
-	for (int part = 0; part < key_data->part_count; ++part) {
+	int part_count = MIN(key_def->part_count, key_data->part_count);
+	for (int part = 0; part < part_count; ++part) {
 		u8 *data = part_data;
 		u32 len = load_varint32((void**) &data);
 
diff --git a/test/box_big/lua.result b/test/box_big/lua.result
index 5d6f808e4a056249dcf179348fd3907ae2eb26ad..354aae4839578abfca70aca423aa7e87a21e48e8 100644
--- a/test/box_big/lua.result
+++ b/test/box_big/lua.result
@@ -11,6 +11,13 @@ lua box.space[1].index[1]:max()
 call box.select(1, 1, 'new', 'world')
 Found 1 tuple:
 ['brave', 'new', 'world']
+#
+# A test case for Bug #904208
+# "assert failed, when key cardinality is greater than index cardinality"
+# https://bugs.launchpad.net/tarantool/+bug/904208
+#
+call box.select(1, 1, 'new', 'world', 'order')
+An error occurred: ER_KEY_CARDINALITY, 'Key cardinality 3 is greater than index cardinality 2'
 call box.delete(1, 'brave')
 Found 1 tuple:
 ['brave', 'new', 'world']
diff --git a/test/box_big/lua.test b/test/box_big/lua.test
index 220fba99827287267e60ad19b3acfafdefc5d95c..6f6ae9891f1d3b2af0f58706ea260c8a54de8c0b 100644
--- a/test/box_big/lua.test
+++ b/test/box_big/lua.test
@@ -3,6 +3,12 @@ exec sql "insert into t1 values ('brave', 'new', 'world')"
 exec admin "lua box.space[1].index[1]:min()"
 exec admin "lua box.space[1].index[1]:max()"
 exec sql "call box.select(1, 1, 'new', 'world')"
+print """#
+# A test case for Bug #904208
+# "assert failed, when key cardinality is greater than index cardinality"
+# https://bugs.launchpad.net/tarantool/+bug/904208
+#"""
+exec sql "call box.select(1, 1, 'new', 'world', 'order')"
 exec sql "call box.delete(1, 'brave')"
 
 #
diff --git a/test/lib/sql_ast.py b/test/lib/sql_ast.py
index 2830a0330f39cd27cc13d2510e5eaeed230a8f8e..6e81abd6793bf517f045221100a69645c265bd66 100644
--- a/test/lib/sql_ast.py
+++ b/test/lib/sql_ast.py
@@ -49,6 +49,7 @@ ER = {
    37: "ER_UPDATE_ID"           ,
    38: "ER_WRONG_VERSION"       ,
    39: "ER_WAL_IO"              ,
+   47: "ER_KEY_CARDINALITY"	,
    48: "ER_PROC_RET"            ,
    49: "ER_TUPLE_NOT_FOUND"     ,
    50: "ER_NO_SUCH_PROC"        ,