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 = 'vi' 
WHERE 
  pfv.variant_id IN (
    76592, 76579, 76580, 76581, 76582, 76583, 
    76584, 76585, 76586, 76587, 76588, 
    76589, 76590, 76591, 76593, 76594, 
    76595, 76597, 76608, 76598, 76618, 
    76617, 76621, 76619, 76620, 76625, 
    76622, 76623, 76624
  )

Query time 0.00288

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": 29,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (76592,76579,76580,76581,76582,76583,76584,76585,76586,76587,76588,76589,76590,76591,76593,76594,76595,76597,76608,76598,76618,76617,76621,76619,76620,76625,76622,76623,76624)"
        }
      },
      {
        "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 = 'vi'"
        }
      }
    ]
  }
}