SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '988542c0cc298c5c50eec7ca57cd688c429e3d16f11e24b6a66d771551bfb0bf' 
  AND token = 'aHurbDLRUiXD+bquEC6Mz/VTTH3kK/CuUvF9O/6CHXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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