SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9acb685ca8e4315051fe42d288a2572882a53191f5ce887f99ef01516d5cef52' 
  AND token = '+1HKRZxqPVZlUTXGjiadBUj7P4vEzqZQlsZty0q43MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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