SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7aa40792d11f4295e544085ebe823d3ddd50995de26fd56d985b98fb1163432' 
  AND token = 'SNB4ekG4z1rZTByrBwyOEsrJsDeybB3crzc2sWPHr70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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