SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5773dc9c13b851e126882177b2851dee51b728c368375da438cc1cb2874da9a7' 
  AND token = 'f0S6d/J+NHxnhl1AVFCRwflHyX8iDgp4EsklPeQnaks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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