SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b87d15ece45995f54935271590c879f60c1e9fc2812ea7ff857d832225900e8' 
  AND token = 'SaNeKQjk3SMUHGBTgCtG8P4gkn1IUdovmf7OhRP2oVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}