SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dca32d9fb5e2aea7a406c6002877bab3f97ad7ec0c8e6bb1109ced1d7c657ab' 
  AND token = 'QnAhf10mtUwjrUbrMvBLeMtAJFcExzWBUIvyzxUvbS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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