SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd2c272945848d967f99db81c3a2e2fdaa5f3bab7fd889dd7b1817e1d26eda5f9' 
  AND token = 'O2AwzuE4JceQHqDg/nEPymfawhTv9ShEAmKSRaEd3Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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