SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93b86be748cfa960f6d919fcae69088b2cf49f642d2edf0967a63eee301879e8' 
  AND token = 'JA5I6eaKIDSK2sZ8IiDxQdUK9M0DYrfuwZp/zLstM5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}