SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87c1be21fb8a9b821db1bcfd84bdb1027c734f531affaaee173257fe4920949a' 
  AND token = 'ndb9x4pm6VJqX9ThcHz/14BumvIxZXigkMh2jBBvvNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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