SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e2a4053755902bd5f2a85cecfa4ba9781b1cade593222f461d781b426d70d47' 
  AND token = 'EfK8UcuUaN6gtvxDrvD3Ubmd04hegoAmoQiOugu0IZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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