SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '27316fe4100f8e8545d4b06aff1e1444441c1206b32f97898ec544c5b8fc3582' 
  AND token = 'qZ5XlGVD79pkBMCjLMwhBUe4bBscTxm/10fDKzUNaQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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