SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a43eb18455fb2c2f6d5cf45d320fc615d8b1389e057e088f22d8758b58064e' 
  AND token = 'NBPZ8O5bUmzZGYyMirPYMJ4XHZDWlog3wIiVZ3EAhzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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