SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3234bf76511c4d71c4631eee987d7e5d56d44330eebf1ca1080a6948abe4834f' 
  AND token = 'dbOJqXhKAq5O5wfZtyEC3YyuUUCcBbk8vqWl9oOyqLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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