SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34460e1c9b719bcadf7c4210f355702b7cfdd9f42a63f437a4a8c6a99bb84f75' 
  AND token = 'OllsYiK7DoBHFhxweS1qDJ91nkC3Uy6jrc8Z28Nzbqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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