SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f55e87ed0a4b84c34fb1de16bfcd6871b66bc4f5aec7d6a76b23289bea9d668' 
  AND token = 'Na1Z/IEAAIA9fLJB3PX/3qbmh9SGdQZIMMr1lM71X7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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