SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b53a23d86aea66095e551275a57e5df3e880b42f7f4e226bd6ba983ff61aaecd' 
  AND token = 'ANh1yBFLknOLuVMlUMqg5p92EdpQ06SQ6k6NhCpiAyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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