SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b2348a2f0202947721f0f654eff8a84870d16c2f6f533c885c35299462a6478' 
  AND token = 'CMJgAJoC8vFZ66HIhWF2N/UQupWBZYzqgyJke5aWWiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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