SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2146409eb8d0e3d671f10421088b9d4b3cfc6a6955ed1bb6c74a43a7662a38da' 
  AND token = '0XMsY+LlUyHmoCGSZZ8uwqhQCAzj+n0BPjCQhqdVs3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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