SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8acb63ca5e969877652ddcfe481b8c683c0edb5d9d7f0846e29441bc9852bdde' 
  AND token = 'VjB8xDPuC5q9IKApxqIM3+C2Qmrw3I8AzUOvYohj7xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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