SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c025cf3026658a9a1a2b5d4d30ace26ed68a4066a29ba3f1f340683a12ef0ea6' 
  AND token = 'XEjNLsbylnxhPVsPSsnh3lBZqMNYIvaUM7e/xwiS61g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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