SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe2dce42d66fe46fae344a544cae31544e28c76b4fde7e4985e9ae44c89b08ff' 
  AND token = 'IxXwDyacmLLZY8BjhoP3NMEuBLwfxcNeI6QfOeYgMsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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