SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd46b9c91bee6d46ecdf934c3fe701f534d2a8d911692482a6383316fa05c593' 
  AND token = 'hrzAQYJu8dZjjKH+p9EpV2hzZJAeCIp/tx01BE7geh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}