SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77fea82997ca813d3af853ff57257ccf59bbcd05820243d923d39cf5549ae2ce' 
  AND token = 'JvBgkTgRqqBKDoTdvYrF1mjhaM/BqrJoptFHqDZzjHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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