SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af27e8057edb6bf8263be564102f84ba1ba0930b28e3a2df7d4dadeaa6141722' 
  AND token = 'x5sEc+XmZvhbE/M8ooGIEJcb+nm4tPcQ3lXGZZYw4zY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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