SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '360defc8c61d038dee3715becfea2b4b642db87bfa3aa8cdb1174ee204d1eda3' 
  AND token = '6GAVaEXZrE7PjWEDbkGbeZT7+WLUy30VyahI4PpGA2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}