SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee0406837fb076724f630e45e42ed513792b249d7db798abcca8dbe8a6baaf4' 
  AND token = 'BSAjyg0oMumL/QjjHQZ4m5ql6uuIT4UinXy+nvZRxHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}