SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b802977fb841bdab7716231c014a04feb2d2397a4a346de4205eedd707f2056' 
  AND token = 'UM66AFfkM/gYRmofqGIirQT8gnr1GblGbuhekiX/TZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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