SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48be83845f95b14dbbbd9db73b1200721f4364e2b94ebdc8903f411fb53ead13' 
  AND token = 'VqFfZhZLFnZu9Y9/LZwcRsPszvY3DoUS6dkMjn+c9Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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