SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '93d469a96b14f9595cc496b5c2f9eba943b135df01c853b586e8021d5d195585' 
  AND token = 'MhJF5Ew6V8Lu2Z9//PCKkeXOGjgTah0zOdPGHQk4VP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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