SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ba1ab63a41a451932594c7294f68a23fce7022da99dc43ee956ee68ce5876a22' 
  AND token = 'gHK4OzoAJyzxIqDiO8PNaavNox2xUIGjCcW/unfvyVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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