SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5220c254af5304e3269d196789ac20fb3a7102916279ca1a986884b2d0ea14' 
  AND token = '7fskLUYw+mJqc2s4ZDorsQYkd/Vb/lWoEVwVCt4dGIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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