SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fda897f920d73ca2311e28c6cc132640cd44519c228250ab023b1031dec07131' 
  AND token = 'Ii1RxQRHjtn2iFXU7Wlcr3UZCYxAzDjoslCXjaRI3cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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