SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dcf63b367c5b927f2e2ff2a0d131f7f2025618d47389a4b191cdeaada8832f6' 
  AND token = 'w7gA6hK1KFQMj0rJ73p1dC2mEgpskGZLv25f7/UQt3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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