SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f19b08427d7dd105769956d92f3786492c2bdeb50bdc4c02361fc709c5114f6' 
  AND token = '/mljjgBuuE0rSuJZxcjqyn3EnY9+h1bWBOYK3c3SH7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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