SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf21371658b4a63c17d559c916f1a9bab9fa35dbdb50be8a954cf826375548f' 
  AND token = 'xNIMtqafFLbY274MTUonP4zUpPDWrzP4evNLiVxBdxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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