SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '478de907ae82f82879f024d6f3037840404ebf4c0ae1281dabc78f6adfe04360' 
  AND token = '4DGyIIQfvFWFyFW7X8uc+auhlEMnqhGADrmnoJJDU7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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