SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f518bf91eb4939631fa94c7dc1d15056eee90348414984d7071240a5fc8b1499' 
  AND token = 'ZmFOoqRaC/GcdCFk8cZe5rNVr+B/XhoJYGsx1n/ZuDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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