getIndexName

string|null public
\Bitrix\Main\DB\Connection::getIndexName(
 string $tableName,
 array $columns,
 boolean $strict = false
);

Its non-static abstract method returns index name.

Parameter	Description	Version
$tableName	Table name.
$columns	Array of index columns.
$strict	The flag indicating that the columns in the index must exactly match the columns in the $Columns parameter.