SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8f8c09088517e004028fb823cb1eb33f912bd2758f7f0f920b43c4b9e407b732' 
  AND token = 'GmkaQeBNnNFCUL1ItpejaoS8ZYV0t3N9ibA9aXTdmqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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