SELECT 
  return_policy_descriptions.policy 
FROM 
  cscart_return_policies AS return_policies 
  LEFT JOIN cscart_return_policy_descriptions AS return_policy_descriptions ON return_policy_descriptions.policy_id = return_policies.policy_id 
  AND return_policy_descriptions.lang_code = 'en' 
WHERE 
  return_policies.object_type = 'company' 
  AND return_policies.object_id = 157

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.70"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "return_policies",
          "access_type": "ref",
          "possible_keys": [
            "object_type"
          ],
          "key": "object_type",
          "used_key_parts": [
            "object_type",
            "object_id"
          ],
          "key_length": "95",
          "ref": [
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.35",
            "data_read_per_join": "112"
          },
          "used_columns": [
            "policy_id",
            "object_type",
            "object_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "return_policy_descriptions",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "policy_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "cscartdb.return_policies.policy_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.70",
            "data_read_per_join": "24"
          },
          "used_columns": [
            "policy_id",
            "policy",
            "lang_code"
          ]
        }
      }
    ]
  }
}