SELECT 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variants.color, 
  cscart_product_feature_variant_descriptions.variant 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variants.variant_id = cscart_product_feature_variant_descriptions.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'es' 
WHERE 
  cscart_product_feature_variants.variant_id IN (
    1944, 1962, 1985, 1953, 1224, 1225, 1228, 
    1235, 1238, 2060, 1535, 1360, 1375, 
    1381, 1987, 1483, 1497, 1499, 1504
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00089

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_product_feature_variants.position, cscart_product_feature_variant_descriptions.variant",
      "temporary_table": {
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_product_feature_variants",
              "access_type": "range",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["variant_id"],
              "rows": 19,
              "filtered": 100,
              "index_condition": "cscart_product_feature_variants.variant_id in (1944,1962,1985,1953,1224,1225,1228,1235,1238,2060,1535,1360,1375,1381,1987,1483,1497,1499,1504)"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variant_descriptions",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["variant_id", "lang_code"],
              "ref": [
                "live_clonned.cscart_product_feature_variants.variant_id",
                "const"
              ],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(cscart_product_feature_variant_descriptions.lang_code = 'es')"
            }
          }
        ]
      }
    }
  }
}

Result

variant_id position color variant
1497 0 #ffffff #boho
1499 0 #ffffff #casual
1504 0 #ffffff #maximalist
2060 0 80% Lycra, 20% Elastano
1985 0 Blanco, Negro, Naranja, Azul.
1235 0 Casual
1944 0 Fábrica Social
1238 0 Formal
1987 0 Gris
1483 0 #ffffff High Rise
1953 0 HUA
1225 0 Lavar a mano
1962 0 Lino
1228 0 Locally made
1360 0 #ffffff Pantalones
1535 0 #ffffff Psicodélicos
1375 0 #ffffff Straight
1224 0 Women
1381 40 #ffffff Largo