SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f248ea65e97bb8ed92e55db782edf44621ae3202bf57f85c40e1805dbdf89e' 
  AND token = 'ppxWSuvkNcakSg8daTEJ6r2x4d9NyA40GPFnO1+Fxc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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