SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34e857d3cd9e6c99accd455e68620bc47f3b764872e5b8d9e59fd5586480a1ad' 
  AND token = 'vPvalq5Il3wggTvFIrKOJPzAHmN8h2eBeMXzm+DV1gM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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