SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3d4bfcc0d1fb05c87f805e7a4fece6265e099ab56c37e966029042513e9438c' 
  AND token = 'dY9xVjcKAbQCchDzpf4DlAzf+sM/ICFpuvvwLqUDWuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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