SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2721a2ae4ae41248316aced28cde6222dd3ed252f517c3fe49d7c881f6a40f54' 
  AND token = 'oo7eSR7GByEhZNXKqdEc8zFTJFRUfhL/m1K8sJrFEf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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