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 = 7263 
WHERE 
  cscart_products_categories.product_id IN (
    95362, 95363, 95364, 95392, 95393, 95442, 
    95592, 95593, 95594, 95595, 95596, 
    95597, 95598, 95599, 95600, 95601, 
    95602, 95603, 95604, 95605, 95606, 
    95607, 95608, 95609, 95610, 95611, 
    95612, 95613, 95614, 95615, 95616, 
    95617, 95618, 95619, 95620, 95621, 
    95622, 95623, 95624, 95625, 95626, 
    95627, 95628, 95764, 95766, 95767, 
    95780, 95781, 95782, 95783, 95784, 
    95785, 95829, 95890, 95893, 95925, 
    95926, 96490, 96491, 96492, 96493, 
    96531, 96532, 96533, 96534, 96535, 
    96536, 96562, 96563, 96630, 96631, 
    96632, 96633, 96634, 96635, 96636, 
    96637, 96638, 96639, 96640, 96641, 
    96642, 96643, 96644, 96645, 96646, 
    96647, 96648, 96649, 96650, 96651, 
    96652, 96653, 96654, 96655, 96656
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00234

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "54.77"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 96,
            "rows_produced_per_join": 96,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "9.89",
              "eval_cost": "9.60",
              "prefix_cost": "19.49",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (95362,95363,95364,95392,95393,95442,95592,95593,95594,95595,95596,95597,95598,95599,95600,95601,95602,95603,95604,95605,95606,95607,95608,95609,95610,95611,95612,95613,95614,95615,95616,95617,95618,95619,95620,95621,95622,95623,95624,95625,95626,95627,95628,95764,95766,95767,95780,95781,95782,95783,95784,95785,95829,95890,95893,95925,95926,96490,96491,96492,96493,96531,96532,96533,96534,96535,96536,96562,96563,96630,96631,96632,96633,96634,96635,96636,96637,96638,96639,96640,96641,96642,96643,96644,96645,96646,96647,96648,96649,96650,96651,96652,96653,96654,96655,96656))"
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 4,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "24.00",
              "eval_cost": "0.48",
              "prefix_cost": "53.09",
              "data_read_per_join": "12K"
            },
            "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": "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": 4,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.20",
              "eval_cost": "0.48",
              "prefix_cost": "54.77",
              "data_read_per_join": "76"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}