SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9b2436ae8421539804c42424646306d45905bb0241c0033f108aa84a5350cf6e' 
  AND token = 'UwAbSS7kfgM0FlDTJSUbJ2SruzEcGbTqi4frBKdQBQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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