SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b72256ff560d5f49718894078f7677efe8bf2e335a158ab2f6bd188754a74789' 
  AND token = 'Kp/xlBSBtCqAa8aIlydZa++vz4uZx2ApVIpyHikmdNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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