SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c64e5a85f0fa2233ef2085ada6d17e936e2db34c6a05ab9ba8be5680fbdc6c' 
  AND token = 'HxvvThwP9fmAZ+OkmZpg1g/3zwujV98xvG/+KyDnD7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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