SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e6fc72beb55ec297741526eb69f9f490236c28e8b112eace3d1e05db80858fb' 
  AND token = 'iDVT5necfCPIxF5bTaLzSjrnEiTG/ghiG/+SDsHhx6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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