SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '450166d597e3f305e848b5571efd0c6802f52d20afc2acda563fe11b7e732af1' 
  AND token = '8Hj/i1qVr5jMxMpvxg2uI9HPJppVsQbEZxVOHyjShgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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