SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f5567633181d88766e3b8d1c267f7d69f461fbec1526d36ec1f23f6a5df7e96' 
  AND token = 'xveRL2h1HPuUvrNazyeZhBbIifV66pLbh30NJl42Vko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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