SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2470819d2dc119bd7aad5bb0c454bff496c9351283dfb28e93c296cb040c20a' 
  AND token = 'URz8Kz3Ch0czaK2DMvVNl4ePRuJlAzvTeVa/IE4WEo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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