SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11bd8536184c9fc55b2d94d8333145ffd7ce76615bcecabd011b2f1b4bda817a' 
  AND token = 'KYI++XGmHQeBtKCZ74jj4ViwXLFRLZWpnVqCrTU6yPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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