SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfefae94e872a4eb84f9c16ff69a517850daa46d7abb5081ebd01f58155f7172' 
  AND token = 'xXNuRySFpYbWtZENmsRC1f1RJGrGxkAuy3JlSXdwnUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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