SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9171521020e70c4fd433ea2fdac8bee67bfd19e014646c4605f4657f48f85d2' 
  AND token = 'KVRGD1NzKWApoz8Oru+oQvFov0U6e2TstM0nRDb9H3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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