SELECT 
  cscart_profile_fields.*, 
  cscart_profile_field_descriptions.description, 
  cscart_profile_fields.checkout_required as required 
FROM 
  cscart_profile_fields 
  LEFT JOIN cscart_profile_field_descriptions ON cscart_profile_field_descriptions.object_id = cscart_profile_fields.field_id 
  AND cscart_profile_field_descriptions.object_type = 'F' 
  AND lang_code = 'en' 
  INNER JOIN cscart_ult_objects_sharing ON (
    cscart_ult_objects_sharing.share_object_id = cscart_profile_fields.field_id 
    AND cscart_ult_objects_sharing.share_company_id = 1 
    AND cscart_ult_objects_sharing.share_object_type = 'profile_fields'
  ) 
WHERE 
  1 = 1 
  AND cscart_profile_fields.profile_type = 'U' 
  AND cscart_profile_fields.checkout_show = 'Y' 
ORDER BY 
  cscart_profile_fields.position

Query time 0.00116

JSON explain

{
  "query_block": {
    "select_id": 1,
    "read_sorted_file": {
      "filesort": {
        "sort_key": "cscart_profile_fields.position",
        "table": {
          "table_name": "cscart_profile_fields",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "checkout_show"],
          "key": "checkout_show",
          "key_length": "4",
          "used_key_parts": ["checkout_show"],
          "ref": ["const"],
          "rows": 23,
          "filtered": 100,
          "index_condition": "cscart_profile_fields.checkout_show = 'Y'",
          "attached_condition": "cscart_profile_fields.checkout_show <=> 'Y' and cscart_profile_fields.profile_type = 'U'"
        }
      }
    },
    "table": {
      "table_name": "cscart_profile_field_descriptions",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "12",
      "used_key_parts": ["object_id", "object_type", "lang_code"],
      "ref": [
        "herbaria_cscart_4_18.cscart_profile_fields.field_id",
        "const",
        "const"
      ],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(cscart_profile_field_descriptions.object_type = 'F' and cscart_profile_field_descriptions.lang_code = 'en')"
    },
    "table": {
      "table_name": "cscart_ult_objects_sharing",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "159",
      "used_key_parts": [
        "share_object_id",
        "share_company_id",
        "share_object_type"
      ],
      "ref": [
        "herbaria_cscart_4_18.cscart_profile_fields.field_id",
        "const",
        "const"
      ],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "cscart_ult_objects_sharing.share_object_id = cscart_profile_fields.field_id and cscart_ult_objects_sharing.share_object_type = 'profile_fields'",
      "using_index": true
    }
  }
}

Result

field_id field_name profile_show profile_required checkout_show checkout_required partner_show partner_required storefront_show field_type position is_default section matching_id class wrapper_class autocomplete_type profile_type description required
6 firstname Y Y Y N Y Y Y I 20 Y C 0 U First Name N
7 lastname Y Y Y N Y Y Y I 30 Y C 0 U Last Name N
39 email Y Y Y Y Y Y Y E 45 Y C 0 off U E-mail (for invoice information) Y
9 phone Y N Y Y Y N Y P 50 Y C 0 U Phone Y
14 b_firstname Y Y Y Y Y Y Y I 90 Y B 15 U First Name Y
16 b_lastname Y Y Y Y Y Y Y I 100 Y B 17 U Last Name Y
37 email N N Y Y Y N Y E 105 Y B 38 billing-email U E-mail Y
18 b_address Y Y Y Y Y Y Y I 110 Y B 19 U Address Y
20 b_address_2 Y N Y N Y N Y I 120 Y B 21 U Address, Line 2 N
22 b_city Y Y Y N Y Y Y I 130 Y B 23 U City N
24 b_state Y Y Y N Y Y Y A 150 Y B 25 U State/Province N
28 b_zipcode Y Y Y Y Y Y Y Z 160 Y B 29 U Zip/Postal Code Y
26 b_country Y Y Y N Y Y Y O 170 Y B 27 U Country N
15 s_firstname Y Y Y Y Y Y Y I 180 Y S 14 U First Name Y
40 b_billing_phone Y N Y Y Y N Y P 180 N B 41 U Phone Y
41 s_billing_phone N N Y Y Y N Y P 180 N S 40 U Phone Y
17 s_lastname Y Y Y Y Y Y Y I 190 Y S 16 U Last Name Y
19 s_address Y Y Y Y Y Y Y I 200 Y S 18 U Address (for USPS shipment) Y
38 email N N Y Y Y N Y E 205 Y S 37 shipping-email U E-mail Y
21 s_address_2 Y N Y N Y N Y I 210 Y S 20 U Address, Line 2 N
23 s_city Y Y Y Y Y Y Y I 220 Y S 22 U City Y
25 s_state Y Y Y Y Y Y Y A 240 Y S 24 U State/Province Y
29 s_zipcode Y Y Y Y Y Y Y Z 250 Y S 28 U Zip/Postal Code Y
27 s_country Y Y Y Y Y Y Y O 260 Y S 26 U Country Y