SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35995b2ffbd498a666087b701a9b140dacc5b0c05e98974f6702501068e2e539' 
  AND token = 'Pp5cPW1vTOSGFq5chPp9rzKmrgG31tSnCePuSwni1xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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