SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bf770f73a164215934597a88c194fd80c7bcf60b686933e9c5a066e7915a1a2' 
  AND token = 'dpjXozIlL/XadgYas2qLFbrEfUUREe1dIf/9yOu/jgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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