SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e9cbe2094d8105429e559cbad9f7e7109eac243bd369d9a8bee7cc1e848640f' 
  AND token = 'DZVI8D7O4xNYK+cfFjBwAAl+Pk4/Z6kwHX+GicMGjDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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