SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f52419740793037233a3f3a4f9a591481e9d4879934c85390a3bba0b1807abaf' 
  AND token = '57nnJnTcfL1JvtamNZqeX+W/QS/2Gr24nq4fsr+jRtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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