SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c717cc309f9e8e37a402e2b502bd0a354f455d7a83e596ddd59b412e96295f4f' 
  AND token = 'EP/dzQbIzpx8UQZN+47yJHqQpheQgmctZlotWv7TnJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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