SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbf57dcc1f81ed246a4a7a8ad0dfc4b6cc79ade0b3bea6e84d4b76939fe83d92' 
  AND token = '5cA5Xz040I3NHckUDe+jM8aUnm1YKjgYWCDjbkQU30M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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