SELECT 
  * 
FROM 
  cscart_bm_locations as l 
  LEFT JOIN cscart_bm_locations_descriptions as d ON d.location_id = l.location_id 
  AND d.lang_code = 'ru' 
WHERE 
  l.layout_id = 12 
  AND l.dispatch IN ('pages.view') 
  AND (
    FIND_IN_SET(48, l.object_ids) 
    OR l.object_ids = ''
  ) 
ORDER BY 
  l.object_ids desc 
LIMIT 
  1

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "read_sorted_file": {
      "filesort": {
        "sort_key": "l.object_ids desc",
        "table": {
          "table_name": "l",
          "access_type": "ALL",
          "rows": 462,
          "filtered": 100,
          "attached_condition": "l.layout_id = 12 and l.dispatch = 'pages.view' and (find_in_set(48,l.object_ids) or l.object_ids = '')"
        }
      }
    },
    "table": {
      "table_name": "d",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "10",
      "used_key_parts": ["location_id", "lang_code"],
      "ref": ["noframes_angrybeaver.l.location_id", "const"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(d.location_id = l.location_id and d.lang_code = 'ru')"
    }
  }
}

Result

location_id dispatch is_default layout_id object_ids custom_html position user_class lang_code name title meta_description meta_keywords
238 pages.view 0 12 48 <meta name="robots" content="noindex" /> <!-- Yandex.Metrika counter --> <script type="text/javascript" > (function(m,e,t,r,i,k,a){m[i]=m[i]||function(){(m[i].a=m[i].a||[]).push(arguments)}; m[i].l=1*new Date(); for (var j = 0; j < document.scripts.length; j++) {if (document.scripts[j].src === r) { return; }} k=e.createElement(t),a=e.getElementsByTagName(t)[0],k.async=1,k.src=r,a.parentNode.insertBefore(k,a)}) (window, document, "script", "https://mc.yandex.ru/metrika/tag.js", "ym"); ym(102434808, "init", { clickmap:true, trackLinks:true, accurateTrackBounce:true, webvisor:true }); </script> <noscript><div><img src="https://mc.yandex.ru/watch/102434808" style="position:absolute; left:-9999px;" alt="" /></div></noscript> <!-- /Yandex.Metrika counter --> <!-- Marquiz script start --> <script> (function(w, d, s, o){ var j = d.createElement(s); j.async = true; j.src = '//script.marquiz.ru/v2.js';j.onload = function() { if (document.readyState !== 'loading') Marquiz.init(o); else document.addEventListener("DOMContentLoaded", function() { Marquiz.init(o); }); }; d.head.insertBefore(j, d.head.firstElementChild); })(window, document, 'script', { host: '//quiz.marquiz.ru', region: 'ru', id: '68414eba2bb79c001958fd2e', autoOpen: false, autoOpenFreq: 'once', openOnExit: false, disableOnMobile: false } ); </script> <!-- Marquiz script end --> <script>(function(t, p) {window.Marquiz ? Marquiz.add([t, p]) : document.addEventListener('marquizLoaded', function() {Marquiz.add([t, p])})})('Inline', {id: '68414eba2bb79c001958fd2e', buttonText: '«Старт»', bgColor: '#bdfa05', textColor: '#363636', rounded: true, shadow: 'rgba(189, 250, 5, 0.5)', blicked: true, buttonOnMobile: true})</script> 460 ru Оптовикам B2B Мебельные ткани оптом для фабрик, мастерских и магазинов – склад в Москве Оптовые поставки мебельных тканей от 20 м — склад в Москве, доставка по РФ