SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b524efbdfbe43bcf0a915d0cb2613a3a6e55abce24eb3a0299cf83dccdf111af' 
  AND token = 'lRRIwhbDDpxhOkQ7knmgnx5RxRUEdr3935KYLbnP7F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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