SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a12bf48ebce6cd037c2532ce45d42b5901a2bfb35f70ce4303cfefad60048b9a' 
  AND token = 'WcSXLijVVp/toBjw7f8xzvPjvI9d7qyUujvZJJ0aXOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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