SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac4a74b882858a63957ba5d9ddd16e9b90982178b9b373fcd2b518f48a95c56' 
  AND token = 'RaFFrPy7ZXQHxiJU6tw+Oq9VOhAmYvx8G4ZkaObXzjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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