SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c8255fe7835604f0aa48cad41d1d407f1823fe7b93db5e9bd5dd6639b2f713d' 
  AND token = 'pjJ3HudMjpg45fIz5qlulvOvTE21YVzJIYiwiJTdQm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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