SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd260fc4422caa60e896861cc9487283c26dd679f2a308cad976e21522c7c1fc4' 
  AND token = 'WdyAyouGGTdvvrzqZL7gB6Zil45wyOoviQ3r6mOrmQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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