SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4fe73dcff8ede179c1d088dfc05eba44dc6208ee1ea1e33f51956c2f3ec38c8' 
  AND token = 'vbKeh+zkorJjalBumBFjGTNQWL6OK7VJn45N1OUM0CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}