SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f93e10604218ea83b87112a936228b808c31e07cfe11a465d8007f12a212fa1b' 
  AND token = 'aYE/CGlghV9EWpi7AWs9VdNPwy4xSI4mXdlUS89juI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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