SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d79fde622f194fac93b0a52e4fab3bff0d2ca6f76c3f47f0a05fd92fdadf78' 
  AND token = 'CqGotdND2z+aE46nGJ5Z8zUXOW83HxLg6NUOXsf+Rl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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