SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 7336 
WHERE 
  cscart_products_categories.product_id IN (
    96602, 96603, 96606, 96608, 96610, 96612, 
    96613, 96616, 96617, 96618, 96619, 
    96625, 96626, 96627, 96628, 96629, 
    96668, 96669, 96670, 96671, 96672, 
    96673, 96674, 96675, 96676, 96680, 
    96681, 96682, 96683, 96686, 96687, 
    96688, 96689, 96690, 96691, 96692, 
    96698, 96699, 96700, 96701, 96702, 
    96703, 96704, 96705, 97874, 97883, 
    97884, 97885, 97887, 97889, 98421, 
    98424, 98425, 98426, 98428, 98432, 
    98434, 98436, 98437, 98438, 98442, 
    98446, 98449, 98450, 98452, 98455, 
    98485, 98486, 98487, 98488, 98489, 
    98491, 98493, 98494, 98495, 98503, 
    98504, 98505, 98506, 98507, 98508, 
    98722, 98723, 98724, 98725, 98726, 
    98727, 98728, 98729, 98730, 98731, 
    98732, 98733, 98734, 98735, 98736
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01703

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "135.66"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "10.30"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 208,
            "rows_produced_per_join": 8,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "20.72",
              "eval_cost": "0.83",
              "prefix_cost": "21.55",
              "data_read_per_join": "21K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`nuie_scalesta_net`.`cscart_categories`.`storefront_id` in (0,1)) and ((`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`))) and (`nuie_scalesta_net`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 117,
            "rows_produced_per_join": 10,
            "filtered": "1.05",
            "cost_info": {
              "read_cost": "2.33",
              "eval_cost": "1.03",
              "prefix_cost": "121.75",
              "data_read_per_join": "164"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (96602,96603,96606,96608,96610,96612,96613,96616,96617,96618,96619,96625,96626,96627,96628,96629,96668,96669,96670,96671,96672,96673,96674,96675,96676,96680,96681,96682,96683,96686,96687,96688,96689,96690,96691,96692,96698,96699,96700,96701,96702,96703,96704,96705,97874,97883,97884,97885,97887,97889,98421,98424,98425,98426,98428,98432,98434,98436,98437,98438,98442,98446,98449,98450,98452,98455,98485,98486,98487,98488,98489,98491,98493,98494,98495,98503,98504,98505,98506,98507,98508,98722,98723,98724,98725,98726,98727,98728,98729,98730,98731,98732,98733,98734,98735,98736))"
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "nuie_scalesta_net.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 10,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.58",
              "eval_cost": "1.03",
              "prefix_cost": "125.35",
              "data_read_per_join": "164"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}