SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5721a82b2a32351915d53d491621d73ebc6f66c59953dc7a3d33bbc8f2567465' 
  AND token = 'SMhKFAzQdFfOJ5mBLVGie1MR9HVhc+6u2VM0ZgZ/ryI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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