SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31c287b9dde38704e4b1e3018be08fc1ea74d5c8fd0b243f18c86218197a81c6' 
  AND token = 'EbAKSqFWRPNye8/fU31GZKAHmCqMidGO57slraYcBv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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