SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    83069, 83070, 83071, 83072, 83073, 83074, 
    83075, 83085, 83076, 83077, 83078, 
    83079, 83080, 83081, 83082, 83083, 
    83084, 83104, 83088, 83087, 83086, 
    83430, 83439, 83431, 83432, 83433, 
    83434, 83435, 83436, 83437, 83438
  )

Query time 0.02021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 31,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (83069,83070,83071,83072,83073,83074,83075,83085,83076,83077,83078,83079,83080,83081,83082,83083,83084,83104,83088,83087,83086,83430,83439,83431,83432,83433,83434,83435,83436,83437,83438)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "pfvd.lang_code = 'en'"
        }
      }
    ]
  }
}