SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '996e75a9af506676a36544b257fdc1c77af4db3a4e8ce6376b43fefe57c2f45d' 
  AND token = 'cqOmEz1ePBgC2pdwP9SIHT6mOw5BWkzbFsPmkUpACYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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