SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b3f4238985251efc867d8b4f75174477ec061df6be3330622f707560d1475ab' 
  AND token = 'DpIerwNc3l73pe+1veJq6MYpZynnWWVPD+bvmlCj+uQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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