SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82dbdc024bacbe02cd2237b8a0f0b131b7dfdc57da7c8c8c8f1fefb3be790f1e' 
  AND token = 'zUdbpluodKwDKNrZ4IaTh6gV8rdAuZpZNaat1geq/vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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