SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a5a6cc09b3a807a6c408c8d365a5f3bb09f46f8eb84d6616cea46427f0adce' 
  AND token = 'PAYQIAvt6FZBKe/AZcHMdiXxGqCRLKJRDvP7BsUiYGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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