SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fae9f720114781a40f12298c10c6828f712ac81dd791996c9e2f7ac6ddf07ac2' 
  AND token = '5Iz9yFrpNHvazTcYvb6DPSBFqdHJY/BbaV7OkV7vRv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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