SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b703176665f706e810322a941fed3a8bd444cdc294193a1557f61cb21e985fb' 
  AND token = 'hqUcHIXXIzabeQ+rbrirUXndvyDYSNKJFGu+HnO4R/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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