SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b217c5280ecbe31dc26f716e24c377d99a70e29d0873a373854369438b453ac' 
  AND token = 'oGFiMqAuyCZbO2iboOcjPjmHmCbghDv07ZdfOTddJow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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