SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd573819b08f0e975be10ee5b4adc334a4810b81a6803cc7f1953b6e1971c2af7' 
  AND token = 'ARPfNEosBMKsBc7unnS4BljagXqxVVz65Jt7QHLGdjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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