SELECT 
  `screen` 
FROM 
  `cscart_company_banner` 
WHERE 
  `company_id` = 687

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.55"
    },
    "table": {
      "table_name": "cscart_company_banner",
      "access_type": "ALL",
      "rows_examined_per_scan": 3,
      "rows_produced_per_join": 1,
      "filtered": "33.33",
      "cost_info": {
        "read_cost": "0.45",
        "eval_cost": "0.10",
        "prefix_cost": "0.55",
        "data_read_per_join": "2K"
      },
      "used_columns": [
        "company_id",
        "screen"
      ],
      "attached_condition": "(`dev2`.`cscart_company_banner`.`company_id` = 687)"
    }
  }
}