SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ae8310f44a10e426bb24046343100aeadc2aae390c63a9847ed95fa349101b' 
  AND token = 'hqa+hB67kg/+hdspP7KCK0HNnnB7cmyK1IFgSoHfqs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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