SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '818a8602b01e2ef5ab72078aa41624f58052ec68c18b890603816d7123bf387e' 
  AND token = 'EYT4jrrzlwytr7OZsPygEaJbxvxe1XqmSCW+BWWxosw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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