SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd3f0a59d91088482cd176ff3ab701845688f14079f8a0af93291c6e5a0dfe1' 
  AND token = 'ZaAS/IQq0B0tXGJ1qIdicWeTvZSycrCKwXVapjulbcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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