SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58c535e7d76fe467a5154cf4eaa84b424137c620494abba87cca27da2a84af5f' 
  AND token = 'LgdiAoPmy1bf541PODpxirk6xNM0Tnml+mtCuts2gLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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