SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd74a3e18801607209817ae28b954a9d09ed82722119712e983ac3a54c9c8b7' 
  AND token = 'rIsBQFTrOeVeK8Tey0TtZiKaqWPSuFFVkehLqhgBngc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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