SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63ab7fa27b80e753293085e83016ee25ec941b7479457be265233f4468de8a66' 
  AND token = 'sISfqKTyHBkQOqir9wWTeNZAJGki9Z/PE//NWcTII28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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