SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ef7b7dc985e7ffee0fda2f93fe65dce07e3b31dda39ee571382382a8de6383' 
  AND token = 'KW3Kpo6k8e51ThOydXpZQNz+p50ZGdVcxqiFAzf39Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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