SELECT 
  lang.name, 
  lang.value 
FROM 
  csscart_language_values lang 
WHERE 
  lang.lang_code = 'en' 
  AND lang.name IN (
    'stay_connected', 'exclusive_promotions', 
    'exclusive_promotions_content', 
    'subscribe', 'stay_connected', 'exclusive_promotions', 
    'exclusive_promotions_content', 
    'subscribe'
  )

Query time 0.00056

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "9.61"
    },
    "table": {
      "table_name": "lang",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "lang_code",
        "name"
      ],
      "key_length": "392",
      "rows_examined_per_scan": 4,
      "rows_produced_per_join": 4,
      "filtered": "100.00",
      "index_condition": "((`demoecarter_pos`.`lang`.`lang_code` = 'en') and (`demoecarter_pos`.`lang`.`name` in ('stay_connected','exclusive_promotions','exclusive_promotions_content','subscribe','stay_connected','exclusive_promotions','exclusive_promotions_content','subscribe')))",
      "cost_info": {
        "read_cost": "8.81",
        "eval_cost": "0.80",
        "prefix_cost": "9.61",
        "data_read_per_join": "1K"
      },
      "used_columns": [
        "lang_code",
        "name",
        "value"
      ]
    }
  }
}