SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3438f2fa23592337ab6edeb289ae497fc69ce799b3445963c4687909e0d66751' 
  AND token = 'd3eJK+7qQoQK3YrJ7JHMfTCykdjR/7H1RwrosBrr5Co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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