SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98e219211ca26e379a393f2f08185088af006684f22d033659c7e88861d2e6f8' 
  AND token = 'b5MIPNMoG3BrlEyBuDZOsbwiYuE9iQ2ffyQI57zBd5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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