SELECT 
  cscart_discussion_posts.*, 
  cscart_discussion_messages.message, 
  cscart_discussion_rating.rating_value 
FROM 
  cscart_discussion_posts 
  LEFT JOIN cscart_discussion_messages ON cscart_discussion_messages.post_id = cscart_discussion_posts.post_id 
  LEFT JOIN cscart_discussion_rating ON cscart_discussion_rating.post_id = cscart_discussion_posts.post_id 
WHERE 
  cscart_discussion_posts.thread_id = 3777 
  AND cscart_discussion_posts.status = 'A' 
ORDER BY 
  cscart_discussion_posts.timestamp DESC 
LIMIT 
  0, 10

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.32"
    },
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_discussion_posts",
            "access_type": "ref",
            "possible_keys": [
              "thread_id",
              "thread_id_2"
            ],
            "key": "thread_id",
            "used_key_parts": [
              "thread_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 3,
            "rows_produced_per_join": 0,
            "filtered": "10.00",
            "index_condition": "(`danishecarter_latest`.`cscart_discussion_posts`.`thread_id` <=> 3777)",
            "cost_info": {
              "read_cost": "3.00",
              "eval_cost": "0.06",
              "prefix_cost": "3.60",
              "data_read_per_join": "134"
            },
            "used_columns": [
              "post_id",
              "thread_id",
              "name",
              "timestamp",
              "user_id",
              "ip_address",
              "status"
            ],
            "attached_condition": "(`danishecarter_latest`.`cscart_discussion_posts`.`status` = 'A')"
          }
        },
        {
          "table": {
            "table_name": "cscart_discussion_messages",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "post_id"
            ],
            "key_length": "3",
            "ref": [
              "danishecarter_latest.cscart_discussion_posts.post_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.30",
              "eval_cost": "0.06",
              "prefix_cost": "3.96",
              "data_read_per_join": "7"
            },
            "used_columns": [
              "message",
              "post_id"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_discussion_rating",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "post_id"
            ],
            "key_length": "3",
            "ref": [
              "danishecarter_latest.cscart_discussion_posts.post_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.30",
              "eval_cost": "0.06",
              "prefix_cost": "4.32",
              "data_read_per_join": "4"
            },
            "used_columns": [
              "rating_value",
              "post_id"
            ]
          }
        }
      ]
    }
  }
}

Result

post_id thread_id name timestamp user_id ip_address status message rating_value
115 3777 Doug 1484900700 0 80451060 A Bought it for my mother, she’s not used to phones with a touch screen so that’s her first experience. She’s very happy that we can make video calls through facetime and be in touch with each other every day. She listens to her fav music every day while reading books, she also has a small flower garden and likes to send everyone photos of her flowers, good that photos she takes are crisp, sharp, and vibrant. I think I wrote too many words already so let me cut it short: it’s a great starter phone for children or elders. 4
116 3777 Flynn 1484900700 0 80451060 A Got it as a second phone, thank heavens that it has the same specs as iPhone 5 but in a cheaper plastic case. It also has all functions of the latter, no cut corners or anything. Good thing that Apple knows its job. 5
114 3777 Mary 1484900640 0 80451060 A My first phone ever! My dad bought it for me for my tenth birthday, I love it! 5