SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01fd8a68d0c49932103d0552557ab4d8814395acd92eec152f94a905320e71cf' 
  AND token = '9pgrNXakfCSFgFY6QSXE+0xFtjyWKHkZjq5efVvNhTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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