SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06a20b942ebe15ae521d9981eb63888eea503bf109bbaa4a693ad0afd1fa6ac5' 
  AND token = '8pjKZp65bYP5zqO9Xkw8fJYsgUyZHNn4Y5N36iUPQoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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