SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd79c6824fc4defac5d5c1c7f49517423b12c8c388b2a46fbfb1e8c227e02f97b' 
  AND token = 'YYVPg2SgVvYJO/Jn+ZJYFQlTn2MU5kMuNNhMELhqGFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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