SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6710a68c9a1496bff8a6c4ddbac718ae5a2f062e8353dcac7d1fa6476895a686' 
  AND token = 'AJv3prEH6liJvzzGQY9RNTnewX4fz063G27Wj2SolIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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