SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd216faf29622bfb0932a7483b38bd1bbab76b6df85fe9c770caf2e397f1914ab' 
  AND token = 'nOCbfNLe5bbrgV0Eq9fAIHO8HHMTyZiQGaP9joXTxZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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