SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c28f322de9eab69ec54b42bd11990610d93a975b00e3d5947ae6c390ed7b77ff' 
  AND token = 'MTlzh8gW7kGaCVD0kZuzYKxXaKGETzAMyXwB1WwDF9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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