SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbcd7beb2c3290ad2fc0082d6f5a39ff48a8ae1baed7d27a565d0d6816e65970' 
  AND token = 'mOv8CpbILjzIYP6xTBnl4lnF4uqRjLaTV2Jfj8ZqUWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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