SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '93f7245e33060aecbd3c4f096af3fef45497cf72a95e2049be4657924d5a9c11' 
  AND token = 'OpRdRmdryP5A6St5LKectVh2WR9Xh7JAnIYpEZkMrBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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