SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f1c7fb4b48f21522f600ed12e073be0dbfb5aff7f10eef570f13e246b2698c6' 
  AND token = 'hE0xOcaoYV2zdW/3cdJY8J5tn8jt3AlqhIFsxIJlHGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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