SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 217

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_vd_vendors_relationships",
          "access_type": "ref",
          "possible_keys": ["brand_id"],
          "key": "brand_id",
          "key_length": "4",
          "used_key_parts": ["brand_id"],
          "ref": ["const"],
          "rows": 15,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
3743 217 653 2128 es
3744 217 646 1887 es
3745 217 658 2180 es
3746 217 660 2190 es
3747 217 648 1905 es
3748 217 649 1924 es
3749 217 649 1925 es
3750 217 652 2118 es
3751 217 652 2105 es
3752 217 652 2123 es
3753 217 652 2106 es
3754 217 654 2140 es
3755 217 654 2141 es
3756 217 647 1890 es
5918 217 661 2198 es