SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98bf6ec3ea48756f77858b188fdf53ae618cd9a6f3cff3ccb67a9b9031bb6403' 
  AND token = 'Kp+/jAw3h35WnOBW2pG/inVuajcsuZzOfQ20+IZFUjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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