SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b11eee82cb9df099c5b8264fc7ada3932f243c0da7e0868831eb390d75d8a7de' 
  AND token = 'zlV8M2WpUXK5jZqL+Ka/HdNYFC3QeoPGv+Gg8PfwbEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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