SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dfc673ba4087346ca4096bacfd1629c1f6dc56c4a867baa1d52a27a3240ad9d' 
  AND token = 'RTYcOzbKyLTRwJXkY3DLOrPnXhqTJD9LmgZbeQIOzw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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