SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6eb68470b8d00cfe2b0889709859168ba8de4c0ebe0f64efdac2c0232d21c30b' 
  AND token = 'l960a4Hjtikn3ntdgmYiyxOvzLfRV+uZ9ZUIFcSiHqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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