SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe491cce40f999009abadce6e470aca973ef314b84bd8eeceb4f308455814a40' 
  AND token = 'pjfGQH0PkQTnNfKaxsPXBhk/mK/pzdcEn6j2iS+HDqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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