SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3c8008491c02b00b1c3a4838ea760d1fa47dc589aa4fdb0ab71e68966cdc9672' 
  AND token = 'phQm0PH6Ex6zxJ5hVob9tZlM+5yu9Ah1aOWPLqqFDZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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