SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a3a66eaba22e5536faf22fdb1095168a3c745a9f4033aab307521b61fd605041' 
  AND token = 'D5XT/v96PCD2o7Wzqhe42/kXjIJjKZQ3wVVys6433rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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