SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cab22d71e4af277dd3e645f588989b78c24ac1ae3750dc43d83af683967c2978' 
  AND token = '9JBYnLzdjUzrOhNnKyAJXzoXgi3ZC7pY00lWt7kIQjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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