SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 177

Query time 0.00040

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": 16,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
3048 177 653 2128 es
3049 177 646 1886 es
3050 177 658 2178 es
3051 177 660 2188 es
3054 177 649 1924 es
3055 177 652 2116 es
3056 177 652 2103 es
3057 177 652 2104 es
3058 177 654 2136 es
3059 177 654 2140 es
3060 177 647 1890 es
6941 177 662 2211 es
6940 177 662 2210 es
6939 177 662 2207 es
6938 177 662 2202 es
5878 177 661 2198 es