SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859350c9224b8d46ad45781fc21c098c9a835c15bfadfeca88c18e3b3aa67b2f' 
  AND token = 'QR3ZZQ5UpZLeoeecEWP/Uc+rWKaKUEv/yuFn8SbYpdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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