SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '254f53ae3d5b3166a7caed0ac4991ccdc9316351601f30f17522dc258774c1e3' 
  AND token = 'tNxGq6m45x0N684qMbu75UnM8TC41eZ3+EDRdrqI7W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00076

JSON explain

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