SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd7852d0e91d48fa7fbbfe8d0b35380cccaebb073bf12023836cf981fb0a988' 
  AND token = 'NUykA7Iikk55n54P/iixj56M8hkLKfdB6ohqYyI8eRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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