SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31bdd060be3b1b92759e59221b8fc18e98143f37c75b3d265349ce8e8dc2fae2' 
  AND token = 'SAjVmYihp7tjk1d+DxB3XU9gknppneoNUKBpZRggGe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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