SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae75556f34179d6fa3370d94d22ee8989a4379aefdcff4ad39d160f35be2e505' 
  AND token = 'MuOxBlKTszrq0nCXvb0iEtS97/owV8hdHQMhbvpp2BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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