SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38241ce13ad0a791a983538fa1376573e649cc4871139ae21e2bf36c99eddce9' 
  AND token = 'pkpY84lqiLiDblgHmAmhLuReBWRQqXeiYxz1oFHcZTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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