SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3622fd4d935c4dd9400734c78e5f4671454334ff5f8a163c90feda9d884611' 
  AND token = 'KFNUyEYUv11od9Pj5M+Iw9/+aHSYhGASVLtjQYZQtk0=' 
  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"
    }
  }
}