SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18a41d71a05b93a8934476218a3db3d22595677458124ea5a22b8d5cc4b2cd41' 
  AND token = 'I5kilxhGHNnVyzhPLQPHDkRUU51q2taDwyyrgKpcR2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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