SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b890f3cc56d152023419644dd49e28759e60a83028d02720496afc921fe13d15' 
  AND token = 'diJl5IMxTB1p2XssFq9lOtlW5vPXJ/grjKsx8eAna4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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