SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b437adeb1b44d579a6b532b733ee5cfeb6ace30404a5d8c574baa705775654a' 
  AND token = 'CAzTRXUY2BOifOOoZ5wUWQgnYdplI05PPmzxyoVP2V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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