SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3fae354a3faf153fd0137b52eac14b8803238dbd776f16d08e3f889d9b992179' 
  AND token = '2kC3bO6m4vcJE+KAbmJQe+tmzaJhSumvyGv3KQclwlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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