SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d29cbf6b1f1194f1ca8ccb3db7539726c458ea019f2bfa837e88e46f6c5eff0' 
  AND token = 'GVi6/rQgz12JPi0Y80+4HUL5RbYd8T/CN8XlmsmYTGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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