SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dc8b1982d155adb8a3aff521878579ad537c954a047cd24410e312047aab20f' 
  AND token = 'Ud6W9GZMnHlfN0JJa8rGS8s5KLMtoJ1b2tpxNmAZj3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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