SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a18d4f713940d463c5f5bf638fb7874f27b678c321da85c209ac232f104b81' 
  AND token = 'C0U0r9iNfDQ1XyODL8pMc9DeIRGyzveqJPmSTLwhOG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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