SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cb5a4d4c4db60aaa26788e4c929195ff7599276afcc6a42a10775cde1a2ff44' 
  AND token = 'b+FqctG2zqXfOceTaIo7AdyfAZM1lMEcHsCOrDr7OY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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