SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95f93edc52f2f3eacf522d1539721b868bdaa52e950445486af5197dc9f33c4f' 
  AND token = 'F8zIRUij1mSsiuNBzQ71IVuZ8edTvZ8Gr/slmjjxlcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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