SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81456bc8f857b3442eae636a00d8e0d5ab34cd206c213a97a609b222ad389869' 
  AND token = 'ltN0L+0TTfuXZTx6xbSGN59rwk7Ledy4I9rvHTi36xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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