SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9fcfb9d61d4e87c27cc5ba7e4933d2aabcb9f0ef550eb30706a303fed508b908' 
  AND token = 'ckLoKI/yUmBffduE2B/fUM7jloKG5uzkCWgQko060qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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