SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd35e1b51f69726257bc05ecaeedc433f4a42afe5f0377e976e3bf8965400340c' 
  AND token = 'jKrxbaQ4uKQPsspTXlUEECRKkkn4DrF4K31PtglWwp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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