SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a57b6816daded726b6929119ce656626964cd8ce52313935d841affec716b6c' 
  AND token = 'vyX9v5FRAiJyQrvYQgXtTqNRfxDFuM5AUVBWud6D4Ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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