SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bf780748687dae7648945e080ab4da4fe214e2f8a53490b9e3a59b4272fcb33e' 
  AND token = 'oqHzZCl0vImKgF/PMECUuklQQxXYG/LvLDnKAZGTuew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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