SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '86d51c7649608b719ed946148486036808a3267e225bf505ce4047519fde7390' 
  AND token = 'Oy7Z+TQtCyAhNvgZq4EU4siJWZomkuj9lDe0vtnfs60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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