SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '221791769372184e80828af0c75ca651f318e5a8c72214844bae22038e8256f1' 
  AND token = 'nbA6IHmp9mXu0k5um6oywMO0onKTaQqBYk7zfHoxQf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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