SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90353ae489cc31bfd55fda984469114956d06ed16607c5eea346367ba0b8888e' 
  AND token = 'Yxa2mryT/NGVECIba3leQgKwtw3HYQ4MdZdiwUCN7Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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