SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f84b35208d38fd3dd2706e3ac5453c171d995c4e830d43b0af43d0293d59e60' 
  AND token = 'aNdyZgbOdZRG9MsaaQWtCnk57C14kCb+152evlzMfEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}