SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6462a09df3f6014dcffb8fccdf8d7a96d6ce20d9be15c639f7fc7cc0c2ee886b' 
  AND token = 'Kuwfbll4HMLweCsbX0KlNGmcdSXjHOidFWQPezOzV9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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