SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a8ade0a4623dc18199c6d7b941cc22565ef5ff2e834ee7c247c19dd21dbdc47' 
  AND token = 'FlxdQ1Ex/LkrMf8pTQVCRN1DOjJux5Kvt+jWVm0lSAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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