SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 219

Query time 0.00049

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": 19,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
3764 219 653 2129 es
3765 219 646 1887 es
3766 219 658 2186 es
3767 219 660 2188 es
3768 219 648 1905 es
3770 219 649 1924 es
3771 219 652 2116 es
3772 219 652 2103 es
3773 219 652 2112 es
3774 219 652 2123 es
3775 219 652 2104 es
3776 219 654 2135 es
3777 219 654 2137 es
3778 219 654 2140 es
3779 219 654 2141 es
3780 219 647 1890 es
5920 219 661 2198 es
7058 219 662 2205 es
7059 219 662 2212 es
7060 219 662 2215 es