SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66da6cae98446b62d18c1edb4b8d9502bdeb1eab1780377a332e63a434fd43cf' 
  AND token = 'OeJj4zljhgWMqxolGh3X6gfGxNxnUeFmIReNbIvJNCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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