SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fb15430d7c3857fa7c256b34bcfef412cc9550b3efa2a02c4ee9e6e331ca60c' 
  AND token = 'GCQNzHvSpg7MDqSwBnYwLgsn3GL7Yd/flX5CMUgnaMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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