SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b5397599ce7049caf01c7f25dff19bffb2097ec6079a899b31b615b39a27fa6' 
  AND token = 'oY2LIJDQpZPkvrD2o4BWAUQKgX+ugY7Ut+DjM49n9o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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