SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d401821b3aa684c6627753e1edf93c12adedf750d173bae1dce3e3972e8bea' 
  AND token = 'eggLxuu09M8KITgTfLWgCdeeNWT7GNaTmVumeYZRoQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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