SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 219

Query time 0.00043

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": 20,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
14546 219 661 2198 es
14545 219 649 1924 es
14544 219 648 1905 es
14543 219 654 2141 es
14542 219 654 2140 es
14541 219 654 2137 es
14540 219 654 2135 es
14539 219 647 1890 es
14538 219 662 2212 es
14537 219 660 2188 es
14536 219 658 2186 es
14535 219 652 2104 es
14534 219 652 2123 es
14533 219 652 2112 es
14532 219 652 2103 es
14531 219 652 2116 es
14530 219 646 1887 es
14529 219 653 2131 es