SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e98e2f1f9301452c4071462146105c80c01eaa8dde6adea9f36cacae1944c357' 
  AND token = 'WtfqMuOYEbOS9BmQRSKLP4X0JUMUF6UMqQTiTODs68Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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