SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f7961e08c5b76fcace7b81536be89c881b9c54971dee1ec345cb73aab817106' 
  AND token = 'bWBxKIYKVwePf7xebONGDTGZ2DTHxhKv4keN2uD4i3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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