SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3e3f1deb4d08a573b8a776887cdc167c7b355c380a3e6af825716130ebb43a66' 
  AND token = '1Vp4HG4yypfa20oO+/fcw3cpz+4KGnxK/5R+bsN35Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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